// Numbas version: exam_results_page_options {"name": "Programming extension demo", "metadata": {"description": "

A collection of questions demonstrating the programming extension.

", "licence": "Creative Commons Attribution 4.0 International"}, "duration": 0, "percentPass": "0", "showQuestionGroupNames": true, "shuffleQuestionGroups": false, "showstudentname": true, "question_groups": [{"name": "Python", "pickingStrategy": "all-ordered", "pickQuestions": 1, "questionNames": ["", "", "", "", "", "", "", "", "", "", ""], "variable_overrides": [[], [], [], [], [], [], [], [], [], [], []], "questions": [{"name": "Assign a variable", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

", "help_url": "", "input_widget": "code-editor", "input_options": {"correctAnswer": "if(settings[\"correct_answer_subvars\"],\n render(settings[\"correct_answer\"])\n,\n settings[\"correct_answer\"]\n)", "hint": {"static": false, "value": "\"Write \"+capitalise(language_synonym(settings[\"code_language\"]))+\" code\""}, "language": {"static": false, "value": "language_synonym(settings[\"code_language\"])"}, "placeholder": {"static": false, "value": "if(settings[\"correct_answer_subvars\"],\n render(settings[\"placeholder\"])\n,\n settings[\"placeholder\"]\n)"}, "theme": {"static": true, "value": "textmate"}}, "can_be_gap": true, "can_be_step": true, "marking_script": "mark:\napply(main_error);\napply(show_images);\napply(matplotlib_feedback);\napply(postamble_feedback);\napply(validation_test_feedback);\napply(marking_test_feedback)\n\ninterpreted_answer:\nstudentAnswer\n\nmain_result:\ncode_result[3]\n\nmarking_results:\ncode_result[6..(len(settings[\"tests\"])+6)]\n\nvalidation_results:\ncode_result[(len(settings[\"tests\"])+6)..len(code_result)]\n\nmain_error:\nassert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)\n\nmarking_test_feedback:\nmap(\n let(\n [name,weight,code], test,\n header, \"Test: {name} \",\n if(r[\"success\"],\n let(\n result, r[\"result\"],\n max_credit, weight/total_weight,\n credit, if(result isa \"number\", result, award(1,result)),\n switch(\n credit=0, negative_feedback(header+\"was not passed.\"),\n credit=1, add_credit(max_credit, header+\"was passed.\"),\n add_credit(credit*max_credit, header+\"was partially passed.\")\n )\n )\n ,\n if(settings[\"show_marking_errors\"],\n negative_feedback(\"\"\"There was an error:

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)\n\nvalidation_test_feedback:\nmap(\n let([name,code], test,\n if(r[\"success\"],\n if(r[\"result\"],\n true\n ,\n fail(\"\"\"Your code failed the test {name}.\"\"\");false\n )\n ,\n fail(\"\"\"There was an error running the test {name}:

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)\n\ntotal_weight:\nsum(map(weight,[name,weight,code],settings[\"tests\"]))\n\npre_submit:\n[run_code(code_language,\n [\n matplotlib_preamble,\n variables_as_code(language_synonym(code_language), settings[\"variables\"]),\n render(settings[\"preamble\"]),\n if(trim(settings[\"modifier\"])=\"\", studentAnswer, eval(expression(settings[\"modifier\"]))),\n render(settings[\"postamble\"]),\n matplotlib_postamble\n ]\n +map(code,[name,marks,code],settings[\"tests\"])\n +map(code,[name,code],settings[\"validation_tests\"])\n)]\n\ncode_result:\npre_submit[\"code_result\"]\n\nmain_stdout:\nsafe(main_result[\"stdout\"])\n\ncode_language:\nsettings[\"code_language\"]\n\npreamble_result:\ncode_result[2]\n\npreamble_stderr:\npreamble_result[\"stderr\"]\n\npostamble_result:\ncode_result[4]\n\npostamble_stderr:\npostamble_result[\"stderr\"]\n\npostamble_feedback:\nassert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)\n\nmatplotlib_preamble:\nif(code_language=\"pyodide\",\n safe(\"\"\"\nimport sys\nif 'matplotlib' in sys.modules:\n import matplotlib.pyplot as plt\n plt.clf() \n\"\"\"),\n \"\"\n)\n\nmatplotlib_postamble:\nswitch(\ncode_language=\"pyodide\",\n safe(\"\"\"\nimport sys\nif 'matplotlib' in sys.modules:\n import matplotlib.pyplot as plt\n fig = plt.gcf()\n if fig.get_axes():\n fig.savefig(sys.stdout, format='svg')\n\"\"\"),\n \"\"\n)\n\nmatplotlib_result:\ncode_result[5]\n\nmatplotlib_feedback:\nswitch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n\n\nimages:\nflatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))\n\nshow_images:\nassert(len(images)=0 or not settings[\"show_stdout\"],\n feedback(\"Your code produced the following {pluralise(len(images),'image','images')}:\");\n map(\n feedback(html(x)),\n x,\n images\n )\n)", "marking_notes": [{"name": "mark", "description": "This is the main marking note. It should award credit and provide feedback based on the student's answer.", "definition": "apply(main_error);\napply(show_images);\napply(matplotlib_feedback);\napply(postamble_feedback);\napply(validation_test_feedback);\napply(marking_test_feedback)"}, {"name": "interpreted_answer", "description": "A value representing the student's answer to this part.", "definition": "studentAnswer"}, {"name": "main_result", "description": "

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

", "definition": "map(\n let(\n [name,weight,code], test,\n header, \"Test: {name} \",\n if(r[\"success\"],\n let(\n result, r[\"result\"],\n max_credit, weight/total_weight,\n credit, if(result isa \"number\", result, award(1,result)),\n switch(\n credit=0, negative_feedback(header+\"was not passed.\"),\n credit=1, add_credit(max_credit, header+\"was passed.\"),\n add_credit(credit*max_credit, header+\"was partially passed.\")\n )\n )\n ,\n if(settings[\"show_marking_errors\"],\n negative_feedback(\"\"\"There was an error:

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

", "definition": "map(\n let([name,code], test,\n if(r[\"success\"],\n if(r[\"result\"],\n true\n ,\n fail(\"\"\"Your code failed the test {name}.\"\"\");false\n )\n ,\n fail(\"\"\"There was an error running the test {name}:

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

", "definition": "[run_code(code_language,\n [\n matplotlib_preamble,\n variables_as_code(language_synonym(code_language), settings[\"variables\"]),\n render(settings[\"preamble\"]),\n if(trim(settings[\"modifier\"])=\"\", studentAnswer, eval(expression(settings[\"modifier\"]))),\n render(settings[\"postamble\"]),\n matplotlib_postamble\n ]\n +map(code,[name,marks,code],settings[\"tests\"])\n +map(code,[name,code],settings[\"validation_tests\"])\n)]"}, {"name": "code_result", "description": "

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

", "definition": "if(code_language=\"pyodide\",\n safe(\"\"\"\nimport sys\nif 'matplotlib' in sys.modules:\n import matplotlib.pyplot as plt\n plt.clf() \n\"\"\"),\n \"\"\n)"}, {"name": "matplotlib_postamble", "description": "

A hack to show any figures produced with matplotlib in the stdout.

", "definition": "switch(\ncode_language=\"pyodide\",\n safe(\"\"\"\nimport sys\nif 'matplotlib' in sys.modules:\n import matplotlib.pyplot as plt\n fig = plt.gcf()\n if fig.get_axes():\n fig.savefig(sys.stdout, format='svg')\n\"\"\"),\n \"\"\n)"}, {"name": "matplotlib_result", "description": "

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

", "definition": "assert(len(images)=0 or not settings[\"show_stdout\"],\n feedback(\"Your code produced the following {pluralise(len(images),'image','images')}:\");\n map(\n feedback(html(x)),\n x,\n images\n )\n)"}], "settings": [{"name": "show_input_hint", "label": "Show the input hint?", "help_url": "", "hint": "", "input_type": "checkbox", "default_value": true}, {"name": "code_language", "label": "Code language", "help_url": "", "hint": "The language that the student's code will be written in.", "input_type": "dropdown", "default_value": "pyodide", "choices": [{"value": "pyodide", "label": "Python"}, {"value": "webr", "label": "R"}]}, {"name": "correct_answer", "label": "Correct answer", "help_url": "", "hint": "A correct answer to the part.", "input_type": "code", "default_value": "", "evaluate": false}, {"name": "correct_answer_subvars", "label": "Substitute question variables into the correct answer?", "help_url": "", "hint": "If ticked, then JME expressions between curly braces will be evaluated and substituted into the correct answer.

If not ticked, then the correct answer will be displayed exactly as it is.", "input_type": "checkbox", "default_value": true}, {"name": "show_stdout", "label": "Show stdout?", "help_url": "", "hint": "If ticked, the STDOUT produced after running the student's code will be shown in the feedback.", "input_type": "checkbox", "default_value": true}, {"name": "show_stderr", "label": "Show stderr?", "help_url": "", "hint": "If ticked, the STDERR produced after running the student's code will be shown in the feedback.", "input_type": "checkbox", "default_value": true}, {"name": "show_marking_errors", "label": "Show errors produced by marking tests?", "help_url": "", "hint": "", "input_type": "checkbox", "default_value": false}, {"name": "placeholder", "label": "Placeholder", "help_url": "", "hint": "Initial text for the code editor", "input_type": "code", "default_value": "", "evaluate": false}, {"name": "modifier", "label": "Student code modifier", "help_url": "", "hint": "JME expression to modify the student's submitted code before being passed to the marking template. The student's code is available as the string variable studentAnswer.", "input_type": "code", "default_value": "", "evaluate": false}, {"name": "preamble", "label": "Preamble", "help_url": "", "hint": "This code is run before the student's code. Define anything that the student's code or your tests need.", "input_type": "code", "default_value": "", "evaluate": false}, {"name": "postamble", "label": "Postamble", "help_url": "", "hint": "This code is run after the student's code but before the validation and unit tests.", "input_type": "code", "default_value": "", "evaluate": false}, {"name": "postamble_feedback_whitespace", "label": "Format postamble output as code?", "help_url": "", "hint": "If ticked, any output produced by the postamble will be formatted in monospace font, with whitespace preserved. If not ticked, it'll be presented as prose text or HTML.", "input_type": "checkbox", "default_value": false}, {"name": "tests", "label": "Marking tests", "help_url": "", "hint": "A list of tests used to mark the student's answer.
Each item is a list with three values:
\n

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "George Stagg", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/930/"}], "tags": [], "metadata": {"description": "

This is the simplest demonstration of the \"code\" part type I could think of: assign x = 1.

An alternative answer gives a hint if the studen'ts code doesn't define x at all.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": [], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Assign the value 1 to the variable x.

", "alternatives": [{"type": "mark-code-3", "useCustomName": true, "customName": "x is not defined", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "alternativeFeedbackMessage": "

The variable x is not defined.

Assign a value to x like this:

x = value

", "useAlternativeFeedback": false, "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "x=1", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"x is not defined\", 1, \"'x' not in locals()\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "x=1", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n py_mark_equal('x',1)\n]", "validation_tests": "[\n py_valid_defined('x')\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Compute the standard deviation of a sample using numpy", "extensions": ["programming", "stats"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

The student must write code to compute the standard deviation of an unknown list of measurements.

The suggested answer uses numpy.std.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

The numpy function std computes the standard deviation of an array.

{code_block(\"import numpy\\nnumpy.std(sample)\",\"python\")}

", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": [], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

A set of measurements is stored in the variable sample.

Compute the standard deviation of the sample.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "import numpy\nnumpy.std(sample)", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "import numpy\n\n# Now compute the standard deviation of sample\n", "modifier": "", "preamble": "from random import random\nsample = [random()*10 for i in range(20)]", "postamble": "studentAnswer = _\nimport numpy", "tests": "[\n [\"Standard deviation computed\", 1, \"\"\"\nstudentAnswer == numpy.std(sample)\n\"\"\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Get the first item in a list", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

Given a randomly-generated list, the student must write code to return its first value.

There's an alternative to check if they get the second item, which they might do if they don't realise Python lists are zero-indexed.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

In Python, the first item in a list has index 0.

So, seq[0] returns the first item in seq.

The variable seq is a list.

Write code to get the first item in the list.

", "alternatives": [{"type": "mark-code-3", "useCustomName": true, "customName": "seq[1]", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "alternativeFeedbackMessage": "

In Python, the first element of a list is element 0, not element 1.

", "useAlternativeFeedback": false, "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "seq[0]", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "from random import randrange\n\nseq = list(range(randrange(1000,2000), randrange(2000,3000)))", "postamble": "", "tests": "[\n [\"Got the first element\", 1, \"_ == seq[1]\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "seq[0]", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "from random import randrange\n\nseq = list(range(randrange(1000,2000), randrange(2000,3000)))", "postamble": "studentanswer = _", "tests": "[\n [\"Got the first element\", 1, \"studentanswer == seq[0]\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Get the last item in a list", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

Given an unknown list, the student has to write code to return the last item in the list.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

There are two ways of getting the last item in a list in Python.

The first is quite long-winded: seq[len(seq)-1].

Python has a shorter notation: if you give a negative index, Python takes that from the length of the list automatically: seq[-1].

The variable seq is a list.

Write code to get the last item in the list.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "seq[-1]", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "from random import randrange\n\nseq = list(range(randrange(1000,2000), randrange(2000,3000)))", "postamble": "studentAnswer = _", "tests": "[\n [\"Got the last element\", 1, \"studentAnswer == seq[-1]\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Make a copy of a list", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

Given an unknown list, the student must write Python code to create a copy of it.

There's an alternative to catch the case where the student's variable is just a reference to the original list.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

In Python, a variable is a reference to an object. More than one variable can refer to the same object.

If you wrote list2 = list1, then list2 would refer to the same object as list1, and any changes to list1 would be reflected in list2 as well.

In order to make an independent copy, you should make a slice of list1:

{code_block(\"list2 = list1[:]\", \"python\")}

This creates a new list object, with all the same elements as list1.

The variable list1 contains a list.

Write code to assign a copy of the list to the variable list2.

", "alternatives": [{"type": "mark-code-3", "useCustomName": true, "customName": "Didn't copy", "marks": 0, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "alternativeFeedbackMessage": "

You have assigned list2 to the same object as list1, but not made a copy: if you change list1, list2 will also change.

", "useAlternativeFeedback": false, "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "list2 = list1[:]", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "from random import randrange\nlist1 = [randrange(1,10) for i in range(50)]", "postamble": "", "tests": "[\n [\"list1 == list2\", 1, \"list1 == list2\"]\n]", "validation_tests": "[\n py_valid_defined('list2')\n]", "variables": "dict()"}}], "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "list2 = list1[:]", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "from random import randrange\nlist1 = [randrange(1,10) for i in range(50)]", "postamble": "", "tests": "[\n [\"list2 is equal to list1, but not the same object\", 1, \"list1 == list2 and list1 is not list2\"]\n]", "validation_tests": "[\n py_valid_defined('list2')\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Filter a list", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

The student must write code to filter a given list of numbers, returning only the positive elements.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": [], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Write a function which returns only the positive elements of the given list.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "def positive_elements(seq):\n pass", "modifier": "", "preamble": "", "postamble": "def all_positive(seq):\n return all(x>0 for x in seq)", "tests": "[\n [\"[-1,1,0]\", 1, \"all_positive(positive_elements([-1,1,0]))\"]\n, [\"range(-5,5)\", 1, \"all_positive(positive_elements(range(-5,5)))\"]\n]", "validation_tests": "[\n [\"positive_elements is defined\", \"'positive_elements' in locals()\"],\n [\"positive_elements is a function\", \"callable(positive_elements)\"]\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "List comprehension", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}], "tags": [], "metadata": {"description": "

The student must write a list comprehension to map the elements of a given list.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "

Consider an array of random numbers in the range $[0,1]$, created with:

{code_block(\"import numpy as np\\nx = np.random.rand(100)\",[\"language\":\"python\"])}

", "advice": "

{code_block(\"y = [ a for a in x if a > 0.5]\",[\"language\":\"python\"])}

Note that you might expect len(y) to be somewhere around 50.

Use list comprehension to set y to the elements in the array that are greater than $0.5$

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "y = [ a for a in x if a > 0.5]", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "# Assume that x is already set \ny = ", "modifier": "", "preamble": "import numpy as np\nx = np.random.rand(100)", "postamble": "", "tests": "[\n [\"Correct y\", 1, \"y == [ a for a in x if a > 0.5]\"]\n]", "validation_tests": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Get Python to work out the right answer", "extensions": ["programming"], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}, {"name": "Aamir Khan", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4537/"}], "tags": [], "metadata": {"description": "

This question shows how to use the programming extension's run_code function to run some Python code and use its result in the marking of a non-code part type.

Python is used to calculate the correct answer for a number entry part type. This could be done

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": [], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "pre_submit:\n[run_code(\"pyodide\",[\"\"\"\nsum(x**3 for x in range(10))\n\"\"\"]\n)]\n\ntarget: pre_submit[\"code_result\"][0][\"result\"]\n\nminvalue: target\n\nmaxvalue: target\n\nmark:\n feedback(\"target = {target}\");\n apply(base_mark)", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Compute $\\sum_{i=1}^9 i^3$

", "minValue": "1", "maxValue": "1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Sum of triangular numbers (with optional steps)", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}], "tags": [], "metadata": {"description": "

Asks the student to calculate the sum of the triangular numbers (up to some randomised number).

Steps guide the student through each step in the calculation.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

{code_block(\"import numpy as np\\nn = np.arange(1,101)\\nt = n*(n+1)/2\\ns = sum(t)\",[\"language\":\"python\"])}

", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"nmax": {"name": "nmax", "group": "Ungrouped variables", "definition": "random(100..250#50)", "description": "

The number of triangular numbers to sum

", "templateType": "anything", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["nmax"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": "3", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Set a variable s to the sum of the first {nmax} triangular numbers,

\\[ s = \\sum_{n=1}^{\\var{nmax}}\\frac{n(n+1)}{2} \\]

", "stepsPenalty": 0, "steps": [{"type": "mark-code-3", "useCustomName": true, "customName": "Create an array for n", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Set a variable n to a NumPy array containing the numbers $1$ to $\\var{nmax}$ using the NumPy function arange().

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "n = np.arange(1,nmax+1)", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "import numpy as np\nn = ", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"Correct n\", \n 1, \n \"(np.arange(1,nmax+1) == n).all()\"\n ]\n]", "validation_tests": "[\n py_valid_defined('n'),\n py_valid_isinstance('n','np.ndarray')\n]", "variables": "[\"nmax\":nmax]"}}, {"type": "mark-code-3", "useCustomName": true, "customName": "Create an array of the triangular numbers $n(n+1)/2$", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Use your array n to create an array t containing the triangular numbers.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "t = n*(n+1)/2", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "# You can assume that n is already set\nt = ", "modifier": "", "preamble": "import numpy as np\nn = np.arange(1,nmax+1)", "postamble": "", "tests": "[\n [\"Correct t\", 1, \"(t == n*(n+1)/2).all()\"]\n]", "validation_tests": "[\n py_valid_defined('t')\n]", "variables": "dict(\"nmax\":nmax )"}}, {"type": "mark-code-3", "useCustomName": true, "customName": "Sum the values in t", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Sum the values in t to find the sum s.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "s = sum(t)", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "# You can assume that n and t are already set\ns = ", "modifier": "", "preamble": "import numpy as np\nn = np.arange(1,nmax+1)\nt = n*(n+1)/2", "postamble": "", "tests": "[\n [\"Correct s\", 1, \"s == sum(t)\"]\n]", "validation_tests": "[\n py_valid_defined('s')\n]", "variables": "dict(\"nmax\":nmax )"}}], "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "import numpy as np\nn = np.arange(1,101)\nt = n*(n+1)/2\ns = sum(t)", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "import numpy as np\n\n# Complete the code to find s\n\ns = ", "modifier": "", "preamble": "", "postamble": "print(type(s))", "tests": "[\n [\"Correct s\", 1, \"(sum(np.arange(1,nmax+1)*(np.arange(1,nmax+1)+1)/2) == s).all()\"]\n]", "validation_tests": "[\n py_valid_defined('s'),\n]", "variables": "dict(\"nmax\":nmax)"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Make a plot with matplotlib", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}, {"name": "George Stagg", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/930/"}], "tags": [], "metadata": {"description": "

This question shows how to display a plot generated in matplotlib from code written by the student.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"python_plot_example": {"name": "python_plot_example", "group": "Ungrouped variables", "definition": "safe(\"ax = fig.add_subplot(111)\\nax.plot([1,2,3,4])\")", "description": "", "templateType": "long plain string", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["python_plot_example"], "variable_groups": [], "functions": {"r_load_files": {"parameters": [["files", "list of string"]], "type": "promise", "language": "javascript", "definition": "const mime_types = {\n '.pdf': 'application/pdf',\n '.svg': 'image/svg+xml'\n}\nreturn new Numbas.jme.types.TPromise(Numbas.extensions.programming.language_runners['webr'].load_webR().then(async (webR) => {\n var promises = [];\n files.forEach(filename => {\n promises.push(new Promise((resolve,reject) => {\n setTimeout(async function() {\n try {\n const buf = await webR.getFileData(filename);\n const extension = filename.match(/\\.[^.]*$/)[0];\n const mime_type = mime_types[extension] || 'text/plain';\n var blob = new Blob([buf], {type: mime_type});\n if(mime_type == 'text/plain' || mime_type == 'image/svg+xml') {\n const text = await blob.text();\n resolve({exists: true, text: text, mime_type});\n } else {\n resolve({exists: true, blob: URL.createObjectURL(blob), mime_type});\n }\n } catch(err) {\n resolve({exists: false, error: err.message});\n }\n },10);\n }));\n });\n const results = await Promise.all(promises);\n var o = {};\n results.forEach((value,i) => { o[files[i]] = jme.wrapValue(value); });\n return {\n r_files: new Numbas.jme.types.TDict(o)\n }\n}));"}, "show_pdf": {"parameters": [["url", "string"]], "type": "html", "language": "jme", "definition": "html(\"\"\"\"\"\")"}, "show_svg": {"parameters": [["text", "string"]], "type": "html", "language": "jme", "definition": "html(text)"}, "r_load_package": {"parameters": [["name", "string"]], "type": "anything", "language": "javascript", "definition": "return new Numbas.jme.types.TPromise(Numbas.extensions.programming.language_runners['webr'].load_webR().then(async (webR) => {\n await webR.loadPackage(name);\n return {};\n}));"}}, "preamble": {"js": "Numbas.extensions.programming.language_runners['webr'].load_webR().then(async (webR) => {\n return webR.loadPackage('svglite')\n});", "css": ".part.type-mark-code-3 .feedbackMessages {\n max-width: none;\n max-height: none;\n}\n\n.svglite {\n max-width: 100%;\n height: auto;\n}\n"}, "parts": [{"type": "mark-code-3", "useCustomName": true, "customName": "Make a plot in Python", "marks": "0", "scripts": {}, "customMarkingAlgorithm": "mark:\n feedback(\"Here's your figure:\");\n feedback(html(code_result[3][\"stdout\"])) ", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": false, "showFeedbackIcon": false, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Make a plot using matplotlib. I've already set up a figure, called fig.

{code_block(python_plot_example,\"python\")}

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "import sys\nimport matplotlib\n\nmatplotlib.use('Agg')\nimport matplotlib.pyplot as plt\nfig = plt.figure()\nfig.savefig(sys.stdout, format='svg')", "postamble": "fig.savefig(sys.stdout, format='svg')", "tests": "[\n [\"Test 1\", 1, \"True\"]\n]", "validation_tests": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Exploration activity: Define a class, add methods to it, then use it", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}, {"name": "George Stagg", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/930/"}], "tags": [], "metadata": {"description": "

In four parts, the student builds up the definition of a class representing a rectangle. First they write the constructor, then add methods to compute area and perimeter.

In the final part, they must use the methods to write a function which determines if a rectangle's area is larger than its perimeter.

Validation tests for the first part, testing that the class is defined.

", "templateType": "anything", "can_override": false}, "validation_area": {"name": "validation_area", "group": "Ungrouped variables", "definition": "validation1 + [\n [\"Rectangle has a method 'area'\", \"hasattr(Rectangle,'area')\"]\n]", "description": "

Validation tests for the second part, testing that the Rectangle class has an area method.

", "templateType": "anything", "can_override": false}, "validation_perimeter": {"name": "validation_perimeter", "group": "Ungrouped variables", "definition": "validation_area + [\n [\"Rectangle has a method 'perimeter'\", \"hasattr(Rectangle,'perimeter')\"]\n]", "description": "

Validation tests for the third part, checking that the class has a perimeter method.

", "templateType": "anything", "can_override": false}, "validation_check_rectangle": {"name": "validation_check_rectangle", "group": "Ungrouped variables", "definition": "[\n [\"check_rectangle is defined\", \"'check_rectangle' in locals()\"]\n]", "description": "", "templateType": "anything", "can_override": false}, "postamble": {"name": "postamble", "group": "Ungrouped variables", "definition": "safe(\"# Test variables \\nfrom random import randrange, random\\n\\ndef random_rect():\\n width = randrange(2,10)\\n height = random()*8+2\\n r = Rectangle(width,height)\\n return (r, width, height)\")", "description": "", "templateType": "long plain string", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["last_code", "validation1", "validation_area", "validation_perimeter", "validation_check_rectangle", "postamble"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": true, "customName": "Create the Rectangle class", "marks": "5", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [{"label": "Add an area method", "rawLabel": "", "otherPart": 1, "variableReplacements": [{"variable": "last_code", "definition": "interpreted_answer"}], "availabilityCondition": "answered and credit=1", "penalty": "", "penaltyAmount": 0, "showPenaltyHint": true, "lockAfterLeaving": false}], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": "Create the Rectangle class", "prompt": "

Create a class Rectangle with an __init__ method to set attributes width and height.

It should be possible to call your class like this

{code_block(\"r = Rectangle(2,3)\",[\"language\":\"python\"])}

to create an object r representing a 2 x 3 rectangle.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "class Rectangle:\n def __init__(self, width, height):\n self.width = width\n self.height = height ", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "", "postamble": "{postamble}\n\nr, width, height = random_rect()", "tests": "[\n [\"Rectangle class exists\", 1/5, \"isinstance(r, Rectangle)\"],\n [\"width is defined\", 1/5, \"hasattr(r,'width')\"],\n [\"width attribute is correct\", 1/5, \"r.width == width\"],\n [\"height is defined\", 1/5, \"hasattr(r,'height')\"],\n [\"height attribute is correct\", 1/5, \"r.height == height\"]\n]", "validation_tests": "validation1", "variables": "dict()"}}, {"type": "mark-code-3", "useCustomName": true, "customName": "Add an area method", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [{"label": "Add a perimeter method", "rawLabel": "", "otherPart": 2, "variableReplacements": [{"variable": "last_code", "definition": "interpreted_answer"}], "availabilityCondition": "answered and credit=1", "penalty": "", "penaltyAmount": 0, "showPenaltyHint": true, "lockAfterLeaving": false}], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": "Add methods", "prompt": "

Add an area method to the class, such that, for example

{code_block(\"r = Rectangle(2,3)\\nr.area()\",[\"language\":\"python\"])}

would return the value 6.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "class Rectangle:\n def __init__(self, width, height):\n self.width = width\n self.height = height \n \n def area(self):\n return self.width * self.height", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "{last_code}", "modifier": "", "preamble": "", "postamble": "{postamble}\n\ndef test_area():\n r, width, height = random_rect()\n return r.area() == width*height", "tests": "[\n [\"Area method returns the area.\", 1, \"all(test_area() for i in range(10))\"],\n]", "validation_tests": "validation_area", "variables": "dict()"}}, {"type": "mark-code-3", "useCustomName": true, "customName": "Add a perimeter method", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [{"label": "Use the class", "rawLabel": "", "otherPart": 3, "variableReplacements": [{"variable": "last_code", "definition": "interpreted_answer"}], "availabilityCondition": "answered and credit=1", "penalty": "", "penaltyAmount": 0, "showPenaltyHint": true, "lockAfterLeaving": false}], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": "Add methods", "prompt": "

The perimeter $p$ of a rectangle with side lengths $w$ and $h$ is

\\[ p = 2w + 2h \\]

Add a perimeter method to the class, such that, for example

{code_block(\"r = Rectangle(2,3)\\nr.area()\",[\"language\":\"python\"])}

would return the value 12.

Keep the area method that you defined in the last part.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "class Rectangle:\n def __init__(self, width, height):\n self.width = width\n self.height = height \n \n def area(self):\n return self.width * self.height \n\n def perimeter(self):\n return 2*(self.width + self.height)", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "{last_code}", "modifier": "", "preamble": "", "postamble": "{postamble}\n\ndef test_perimeter():\n r, width, height = random_rect()\n return r.perimeter() == 2*(width + height)", "tests": "[\n [\"Perimeter method returns the perimeter.\", 1, \"all(test_perimeter() for i in range(10))\"],\n]", "validation_tests": "validation_perimeter", "variables": "dict()"}}, {"type": "mark-code-3", "useCustomName": true, "customName": "Use the class", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": "Use the class", "prompt": "

Write a function check_rectangle(r) which takes an instance of your Rectangle class and returns True if its area is bigger than its perimeter.

", "settings": {"show_input_hint": true, "code_language": "pyodide", "correct_answer": "", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "def check_rectangle(r):\n pass", "modifier": "", "preamble": "{last_code}", "postamble": "{postamble}\n\ndef test_fn():\n r, width, height = random_rect()\n print(width, height, width*height > 2*(width+height))\n return check_rectangle(r) == (width*height > 2*(width+height))", "tests": "[\n [\"check_perimeter classifies some random rectangles correctly\", 1, \"all(test_fn() for i in range(10))\"],\n [\"returns False when area equals perimeter\", 1, \"check_rectangle(Rectangle(4,4))==False\"]\n]", "validation_tests": "validation_check_rectangle", "variables": "dict()"}}], "partsMode": "explore", "maxMarks": 0, "objectives": [{"name": "Create the Rectangle class", "limit": "5"}, {"name": "Add methods", "limit": "2"}, {"name": "Use the class", "limit": 1}], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}]}, {"name": "R", "pickingStrategy": "all-ordered", "pickQuestions": 1, "questionNames": ["", "", "", "", "", ""], "variable_overrides": [[], [], [], [], [], []], "questions": [{"name": "Assign a variable", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

The student must write R code to assign the given value to the variable x.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

In R, there are two common ways of assigning a variable:

{code_block(\"x = \"+target,\"r\")}

and

{code_block(\"x <- \"+target,\"r\")}

Both methods are equivalent.

", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"target": {"name": "target", "group": "Ungrouped variables", "definition": "random(0 .. 100#1)", "description": "", "templateType": "randrange", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["target"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Set x equal to {target}.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "x <- {target}", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"x is equal to {target}\", 1, \"x=={target}\"]\n]", "validation_tests": "[\n [\"x exists\", \"exists('x')\"]\n]", "variables": "[\"target\":target]"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Define a vector", "extensions": ["mas-codeassess", "programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}, {"name": "Aamir Khan", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4537/"}, {"name": "James Murray", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/18877/"}], "tags": [], "metadata": {"description": "

The student must write R code to define vectors, in a few ways.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "

a) To define a vector in R and assign it to a variable x we use the c function as follows:

x=c({x_r})

b) To access elements of a vector we use square brackets [] after the name of our vector:

x[{partb_n}]

c) We can also use the seq command to define a vector. Here we wish to define a vector y where the first element is $\\var{partc_a}$ and the sequence increases by a step size of $\\var{partc_step}$ up to $\\var{partc_b}$.

y=seq({partc_a},{partc_b},by={partc_step})

d) To select all of the elements of our vector y that are greater than $\\var{partd_n}$ we again use square brackets around the logical expression we wish to evaluate:

z=y[y>{partd_n}]

e) To define the two vectors a and b we use the seq command but define the total length of the vector using length.out={parte_a_length} (instead of the step size as in part c). We can then apply component-by-component operations to vectors easily:

a=seq({parte_a_a},{parte_a_b},length.out={parte_a_length})
b=seq({parte_b_a},{parte_b_b},length.out={parte_a_length})
d=a+b
e=a*b

", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"x_vector": {"name": "x_vector", "group": "Ungrouped variables", "definition": "vector(repeat(random(1..10),8))", "description": "", "templateType": "anything", "can_override": false}, "x_r": {"name": "x_r", "group": "Ungrouped variables", "definition": "join(x_vector,',')", "description": "", "templateType": "anything", "can_override": false}, "partc_a": {"name": "partc_a", "group": "Ungrouped variables", "definition": "random(1 .. 10#1)", "description": "", "templateType": "randrange", "can_override": false}, "partc_b": {"name": "partc_b", "group": "Ungrouped variables", "definition": "random(100 .. 120#1)", "description": "", "templateType": "randrange", "can_override": false}, "partc_step": {"name": "partc_step", "group": "Ungrouped variables", "definition": "shuffle([0.5,0.25,0.2,0.1])[0]", "description": "", "templateType": "anything", "can_override": false}, "partb_n": {"name": "partb_n", "group": "Ungrouped variables", "definition": "random(2 .. 8#1)", "description": "", "templateType": "randrange", "can_override": false}, "partd_n": {"name": "partd_n", "group": "Ungrouped variables", "definition": "random(50 .. 80#1)", "description": "", "templateType": "randrange", "can_override": false}, "parte_a_a": {"name": "parte_a_a", "group": "Ungrouped variables", "definition": "random(1 .. 10#1)", "description": "", "templateType": "randrange", "can_override": false}, "parte_a_b": {"name": "parte_a_b", "group": "Ungrouped variables", "definition": "random(20 .. 30#1)", "description": "", "templateType": "randrange", "can_override": false}, "parte_a_length": {"name": "parte_a_length", "group": "Ungrouped variables", "definition": "random(100 .. 200#1)", "description": "", "templateType": "randrange", "can_override": false}, "parte_b_a": {"name": "parte_b_a", "group": "Ungrouped variables", "definition": "random(1 .. 10#1)", "description": "", "templateType": "randrange", "can_override": false}, "parte_b_b": {"name": "parte_b_b", "group": "Ungrouped variables", "definition": "random(20 .. 30#1)", "description": "", "templateType": "randrange", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["x_vector", "x_r", "partc_a", "partc_b", "partc_step", "partb_n", "partd_n", "parte_a_a", "parte_a_b", "parte_a_length", "parte_b_a", "parte_b_b"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Give the command to define a vector x that contains the numbers {join(x_vector,',')}.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "x=c({x_r})", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"Correct assignment\", 1, \"all(x==c({x_r}))&length(x)==8\"]\n]", "validation_tests": "[\n [\"Make sure to assign to a variable x\",\"exists('x')\"]\n]", "variables": "dict('x_r':x_r)"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Generate normal random variables", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}, {"name": "Aamir Khan", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4537/"}, {"name": "Laura Midgley", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/18287/"}], "tags": [], "metadata": {"description": "

The student must write R code to generate samples and calculate CDFs of some common distributions.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "", "advice": "", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"mu": {"name": "mu", "group": "Random parameters", "definition": "random(-3 .. 3#1)", "description": "

$\\mu$ used in part a.

", "templateType": "randrange", "can_override": false}, "sigma": {"name": "sigma", "group": "Random parameters", "definition": "random(0.1 .. 1#0.1)", "description": "

$\\sigma$ used in part a

", "templateType": "randrange", "can_override": false}, "n": {"name": "n", "group": "Random parameters", "definition": "random(10 .. 15#1)", "description": "

Random sample size for part a and part b

", "templateType": "randrange", "can_override": false}, "x": {"name": "x", "group": "Random parameters", "definition": "random(1..n)", "description": "

Random x used in Binomial question part b

", "templateType": "anything", "can_override": false}, "p": {"name": "p", "group": "Random parameters", "definition": "random(0.1 .. 0.9#0.1)", "description": "

Random $p$ used for Binomial in part b

", "templateType": "randrange", "can_override": false}, "y": {"name": "y", "group": "Random parameters", "definition": "random(5 .. 10#1)", "description": "

Random y for part c

", "templateType": "randrange", "can_override": false}, "lambda": {"name": "lambda", "group": "Random parameters", "definition": "random(5 .. 10#1)", "description": "

$\\lambda$ for Poisson in part c

", "templateType": "randrange", "can_override": false}, "alpha": {"name": "alpha", "group": "Random parameters", "definition": "random(1 .. 5#0.1)", "description": "

Rate parameter for exponential distribution in part d

", "templateType": "randrange", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": [], "variable_groups": [{"name": "Random parameters", "variables": ["mu", "sigma", "n", "x", "p", "lambda", "y", "alpha"]}], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Give the command to generate $\\var{n}$ random samples from a Normal distribution with $\\mu=\\var{mu}$ and $\\sigma=\\var{sigma}$.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "rnorm({n},{mu},{sigma})", "correct_answer_subvars": true, "show_stdout": false, "show_stderr": false, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "set.seed(2906)", "postamble": "student_answer=.Last.value\nset.seed(2906)", "tests": "[\n [\"Correct calculation\", 1, \"identical(student_answer,rnorm({n},{mu},{sigma}))\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Write an R function to approximate $e$", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

In the first part, the student must write an R function to compute the first $n$ terms of the series $\\frac{1}{k!}$.

In the second part, they must use that function to calculate an approximation to $e$ using a given number of terms of the series.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "

A fun approximation for the mathematical constant $e$ is,

\\[e \\approx 1+\\displaystyle\\sum_{k=1}^{n}\\frac{1}{k!}\\]

Let's calculate it using this method in R!

", "advice": "", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"randn": {"name": "randn", "group": "Ungrouped variables", "definition": "random(2..13)", "description": "

The number of terms of the series to compute.

", "templateType": "anything", "can_override": false}, "series_function": {"name": "series_function", "group": "Ungrouped variables", "definition": "safe(\"series <- function(n) {\\n k = 1:n\\n Sn = 1/factorial(k)\\n return(Sn)\\n}\")", "description": "", "templateType": "long plain string", "can_override": false}, "series_placeholder": {"name": "series_placeholder", "group": "Ungrouped variables", "definition": "safe(\"series = function(n){\\n # Complete the function\\n}\")", "description": "

The initial code for the first part, where the student has to write a function to compute the series $\\frac{1}{k!}$.

", "templateType": "long plain string", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["randn", "series_function", "series_placeholder"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

First, write a function named series that takes an argument n and returns $[S_1, S_2,\\dots S_n]$ as a vector, where $S_k = \\frac{1}{k!}$.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "{series_function}", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": false, "show_marking_errors": false, "placeholder": "{series_placeholder}", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"series function works\", 1, \"\"\"all.equal(series(7),1/factorial(1:7))\"\"\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}, {"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [{"variable": "series_function", "part": "p0", "must_go_first": false}], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Next, use your function to appoximate $e$ using the appoximation above, using a value of $n=\\var{randn}$. Save this into the variable named eapprox.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "eapprox = 1+sum(series({randn}))", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "eapprox <- ", "modifier": "", "preamble": "{series_function}", "postamble": "", "tests": "[\n [\"e approximation is correct\", 1, \"eapprox == (1+sum(1/factorial(1:randn)))\"]\n]", "validation_tests": "[\n [\"eapprox exists\", \"exists('eapprox')\"]\n]", "variables": "dict('randn': randn)"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Query the built-in mtcars dataset", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

Several questions on interrogating the mtcars dataset built in to R.

", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "

The Motor Trend Car Road Tests data frame is built into R with the variable name mtcars.

Before answering this question, first get a feel for the structure of the dataset by using commands such as head(mtcars) and help(mtcars).

", "advice": "

a)

{code_block(part_a_answer,\"r\")}

b)

{code_block(part_b_answer,\"r\")}

c)

{code_block(part_c_answer,\"r\")}

d)

To calculate the maximum horsepower, run

{code_block(part_d_code,\"r\")}

e)

To calculate the mean mpg of cars with 8 cylinders, run

{code_block(part_e_code,\"r\")}

f)

To calculate the 75% quantile, run

{code_block(part_f_code,\"r\")}

", "rulesets": {}, "builtin_constants": {"e": true, "pi,\u03c0": true, "i": true}, "constants": [], "variables": {"num_gears": {"name": "num_gears", "group": "Ungrouped variables", "definition": "random(3..5)", "description": "", "templateType": "anything", "can_override": false}, "disp_val": {"name": "disp_val", "group": "Ungrouped variables", "definition": "20*random(5..20)", "description": "", "templateType": "anything", "can_override": false}, "num_cyl": {"name": "num_cyl", "group": "Ungrouped variables", "definition": "random([4,6,8])", "description": "", "templateType": "anything", "can_override": false}, "part_a_answer": {"name": "part_a_answer", "group": "Ungrouped variables", "definition": "safe(\"gears = mtcars[mtcars$gear == {num_gears},]\")", "description": "", "templateType": "long plain string", "can_override": false}, "part_b_answer": {"name": "part_b_answer", "group": "Ungrouped variables", "definition": "safe(\"displ = mtcars[mtcars$disp>300,]\")", "description": "", "templateType": "long plain string", "can_override": false}, "part_c_answer": {"name": "part_c_answer", "group": "Ungrouped variables", "definition": "safe(\"mercs = mtcars[grep(\\'Merc\\', rownames(mtcars)),]\")", "description": "", "templateType": "long plain string", "can_override": false}, "part_d_code": {"name": "part_d_code", "group": "Ungrouped variables", "definition": "safe(\"max(mtcars$hp)\")", "description": "", "templateType": "long plain string", "can_override": false}, "part_e_code": {"name": "part_e_code", "group": "Ungrouped variables", "definition": "safe(\"mean(mtcars[mtcars$cyl == 8,]$mpg)\")", "description": "", "templateType": "long plain string", "can_override": false}, "part_f_code": {"name": "part_f_code", "group": "Ungrouped variables", "definition": "safe(\"as.numeric(quantile(mtcars[mtcars$cyl==4,]$mpg,0.75))\")", "description": "", "templateType": "long plain string", "can_override": false}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["num_gears", "disp_val", "num_cyl", "part_a_answer", "part_b_answer", "part_c_answer", "part_d_code", "part_e_code", "part_f_code"], "variable_groups": [], "functions": {}, "preamble": {"js": "", "css": ""}, "parts": [{"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Write an R command to create new data frame named gears that contains only the cars with {num_gears} gears.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "{part_a_answer}", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "gears = ", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"Correct data frame\", 1, \"identical(gears, mtcars[mtcars$gear == num_gears,])\"]\n]", "validation_tests": "[\n [\"Data frame 'gears' exists\", \"exists('gears')\"]\n]", "variables": "['num_gears': num_gears]"}}, {"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Write an R command to create new data frame named displ that contains only the cars with more than {disp_val} cu.in. of displacement.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "{part_b_answer}", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "displ =", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"Correct data frame\", 1, \"identical(displ, mtcars[mtcars$disp>disp_val,])\"]\n]", "validation_tests": "[\n [\"Data frame 'displ' exists\", \"exists('displ')\"]\n]", "variables": "['disp_val':disp_val]"}}, {"type": "mark-code-3", "useCustomName": false, "customName": "", "marks": "2", "scripts": {}, "customMarkingAlgorithm": "", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": true, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Write an R command to create new data frame named mercs that contains only the cars with \"Merc\" in their name.

Hint: investigate the grep() function using R's help pages.

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "{part_c_answer}", "correct_answer_subvars": true, "show_stdout": true, "show_stderr": true, "show_marking_errors": false, "placeholder": "mercs =", "modifier": "", "preamble": "", "postamble": "", "tests": "[\n [\"Correct data frame\", 1, \"identical(mercs, mtcars[grep('Merc', rownames(mtcars)),])\"]\n]", "validation_tests": "[\n [\"Data frame 'mercs' exists\", \"exists('mercs')\"]\n]", "variables": "dict()"}}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": 1, "scripts": {}, "customMarkingAlgorithm": "pre_submit:\n[run_code(\"webr\",[part_d_code])]\n\ntarget: dec(\n replace_regex(safe(\"\\\\[1\\\\] \"),\"\",pre_submit[\"code_result\"][0][\"stdout\"],\"g\")\n)\n\nminvalue: target\n\nmaxvalue: target", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": false, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Find the the maximum gross horsepower in the full mtcars dataset.

", "minValue": "1", "maxValue": "1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "showFractionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "2", "scripts": {}, "customMarkingAlgorithm": "pre_submit:\n[\n run_code(\"webr\",[part_e_code])\n]\n\n\ntarget: dec(\n replace_regex(safe(\"\\\\[1\\\\] \"),\"\",pre_submit[\"code_result\"][0][\"stdout\"],\"g\")\n)\n\nminvalue: target\n\nmaxvalue: target", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": false, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Find the mean mpg of cars with 8 cylinders.

", "minValue": "1", "maxValue": "1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "precisionType": "dp", "precision": "1", "precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "strictPrecision": false, "showPrecisionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}, {"type": "numberentry", "useCustomName": false, "customName": "", "marks": "2", "scripts": {}, "customMarkingAlgorithm": "pre_submit:\n[run_code(\"webr\",[part_f_code])]\n\ntarget: dec(\n replace_regex(safe(\"\\\\[1\\\\] \"),\"\",pre_submit[\"code_result\"][0][\"stdout\"],\"g\")\n)\n\nminvalue: target\n\nmaxvalue: target", "extendBaseMarkingAlgorithm": true, "unitTests": [], "showCorrectAnswer": false, "showFeedbackIcon": true, "variableReplacements": [], "variableReplacementStrategy": "originalfirst", "nextParts": [], "suggestGoingBack": false, "adaptiveMarkingPenalty": 0, "exploreObjective": null, "prompt": "

Find the 75% quantile of the mpg of cars with 4 cylinders.

", "minValue": "1", "maxValue": "1", "correctAnswerFraction": false, "allowFractions": false, "mustBeReduced": false, "mustBeReducedPC": 0, "displayAnswer": "", "precisionType": "dp", "precision": "1", "precisionPartialCredit": 0, "precisionMessage": "You have not given your answer to the correct precision.", "strictPrecision": false, "showPrecisionHint": true, "notationStyles": ["plain", "en", "si-en"], "correctAnswerStyle": "plain"}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}, {"name": "Make a plot", "extensions": ["programming"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.

", "input_type": "code", "default_value": "[\n [\"arithmetic works\", \"1+1 == 2\"]\n]", "evaluate": true}, {"name": "variables", "label": "Variables to include in code", "help_url": "", "hint": "Give a dictionary mapping variable names to their values. These variables will be available in the code that is run.", "input_type": "code", "default_value": "dict()", "evaluate": true}], "public_availability": "always", "published": true, "extensions": ["programming"]}], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Chris Graham", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/369/"}, {"name": "George Stagg", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/930/"}, {"name": "Aamir Khan", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4537/"}, {"name": "Laura Midgley", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/18287/"}], "tags": [], "metadata": {"description": "

Demonstrates how to display a plot generated in R.

Write some R code to make a plot. Something like this should do the job:

{code_block(\"hist(rnorm(1000,10,1))\", \"r\")}

", "settings": {"show_input_hint": true, "code_language": "webr", "correct_answer": "", "correct_answer_subvars": true, "show_stdout": false, "show_stderr": true, "show_marking_errors": false, "placeholder": "", "modifier": "", "preamble": "library('svglite')\noutput_filename <- \"test.svg\"\nsvglite(output_filename, standalone=FALSE, fix_text_size=FALSE)", "postamble": "dev.off()\ncat(readChar(output_filename, file.info(output_filename)$size))", "tests": "[\n [\"Looks great!\", 1, \"TRUE\"]\n]", "validation_tests": "[\n]", "variables": "dict()"}}], "partsMode": "all", "maxMarks": 0, "objectives": [], "penalties": [], "objectiveVisibility": "always", "penaltyVisibility": "always"}]}], "allowPrinting": true, "navigation": {"allowregen": true, "reverse": true, "browse": true, "allowsteps": true, "showfrontpage": false, "showresultspage": "oncompletion", "navigatemode": "menu", "onleave": {"action": "none", "message": ""}, "preventleave": false, "startpassword": ""}, "timing": {"allowPause": true, "timeout": {"action": "none", "message": ""}, "timedwarning": {"action": "none", "message": ""}}, "feedback": {"showactualmark": true, "showtotalmark": true, "showanswerstate": true, "allowrevealanswer": true, "advicethreshold": 0, "intro": "", "end_message": "", "reviewshowscore": true, "reviewshowfeedback": true, "reviewshowexpectedanswer": true, "reviewshowadvice": true, "feedbackmessages": []}, "diagnostic": {"knowledge_graph": {"topics": [], "learning_objectives": []}, "script": "diagnosys", "customScript": ""}, "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}, {"name": "Aamir Khan", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/4537/"}], "extensions": ["mas-codeassess", "programming", "stats"], "custom_part_types": [{"source": {"pk": 195, "author": {"name": "Christian Lawson-Perfect", "pk": 7}, "edit_page": "/part_type/195/edit"}, "name": "Code", "short_name": "mark-code-3", "description": "

Mark code provided by the student by running it and a series of validation and marking tests.

The validation tests are used to reject an answer if the student has misunderstood the task, for example if they haven't defined a required variable or function.

Marking tests check properties of the student's code. Each test awards a proportion of the available credit if it is passed.

You can optionally show the student the STDOUT and/or STDERR when running their code.

You can give a preamble and postamble which are run before and after the student's code, and also modify the student's code before running it.

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(r[\"stderr\"])}

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

The result of running the student's code and the preamble, without any tests.

Normally used to detect errors in the student's code.

", "definition": "code_result[3]"}, {"name": "marking_results", "description": "

The results of running the marking tests.

", "definition": "code_result[6..(len(settings[\"tests\"])+6)]"}, {"name": "validation_results", "description": "

The results of running the validation tests.

", "definition": "code_result[(len(settings[\"tests\"])+6)..len(code_result)]"}, {"name": "main_error", "description": "

Show STDOUT if allowed.

Check the student's code runs on its own. Fail if there was an error, and show STDERR if allowed.

", "definition": "assert(main_stdout=\"\" or not settings[\"show_stdout\"],\n feedback(\"Your code produced this output:

{escape_html(main_stdout)}

\")\n);\nassert(main_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in your code:

{escape_html(main_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in your code.\")\n )\n)"}, {"name": "marking_test_feedback", "description": "

Feedback on the marking tests. For each test, if the test was passed then add the corresponding amount of credit. If there was an error, show the error.

{escape_html(r[\"stderr\"])}

\"\"\")\n ,\n negative_feedback(header+\"was not passed.\")\n )\n )\n ),\n [test,r],\n zip(settings[\"tests\"],marking_results)\n)"}, {"name": "validation_test_feedback", "description": "

Give feedback on the validation tests. If any of them are not passed, the student's answer is invalid.

{escape_html(r[\"stderr\"])}

\"\"\")\n )\n ),\n [test,r],\n zip(settings[\"validation_tests\"],validation_results)\n)"}, {"name": "total_weight", "description": "

The sum of the weights of the marking tests. Each test's weight is divided by this to produce a proportion of the available credit.

", "definition": "sum(map(weight,[name,weight,code],settings[\"tests\"]))"}, {"name": "pre_submit", "description": "

The code blocks to run.

In order, they are:

0 - The matplotlib hack preamble (in Python, make sure matplotlib plots are displayed)
1 - Set passed-in variables
2 - Preamble
3 - The student's code
4 - Postamble
5 - The matplotlib hack postamble
Marking tests
Validation tests

The results of the code blocks: a list with an entry corresponding to each block of code.

", "definition": "pre_submit[\"code_result\"]"}, {"name": "main_stdout", "description": "

The stdout from the student's code.

", "definition": "safe(main_result[\"stdout\"])"}, {"name": "code_language", "description": "

The language the code is written in. Either \"pyodide\" (Python) or \"webr\" (R)

", "definition": "settings[\"code_language\"]"}, {"name": "preamble_result", "description": "

The result of running the preamble block.

", "definition": "code_result[2]"}, {"name": "preamble_stderr", "description": "

The STDERR produced by the preamble block.

", "definition": "preamble_result[\"stderr\"]"}, {"name": "postamble_result", "description": "

The result of running the postamble.

", "definition": "code_result[4]"}, {"name": "postamble_stderr", "description": "

The STDERR produced by the postamble block.

", "definition": "postamble_result[\"stderr\"]"}, {"name": "postamble_feedback", "description": "

Show the STDOUT from the postamble, if there is any.

", "definition": "assert(postamble_result[\"stdout\"]=\"\",\n feedback(\n if(settings[\"postamble_feedback_whitespace\"],\n html(\"\"\"

{escape_html(postamble_result[\"stdout\"])}

\"\"\")\n ,\n postamble_result[\"stdout\"]\n )\n )\n);\nassert(postamble_result[\"success\"],\n if(settings[\"show_stderr\"],\n fail(\"\"\"There was an error in the marking routine postamble:

{escape_html(postamble_result[\"stderr\"])}

\"\"\")\n ,\n fail(\"There was an error in the marking routine postamble.\")\n )\n)"}, {"name": "matplotlib_preamble", "description": "

Preamble for a hack to ensure that figures produced by matplotlib in Python are displayed.

This code clears the matplotlib output, if matplotlib has been loaded.

A hack to show any figures produced with matplotlib in the stdout.

The result of running the matplotlib hack.

", "definition": "code_result[5]"}, {"name": "matplotlib_feedback", "description": "

Feedback from the matplotlib hack: if a figure is produced, it's displayed as SVG here.

", "definition": "switch(\ncode_language=\"pyodide\",\n assert(matplotlib_result[\"stdout\"]=\"\",\n feedback(matplotlib_result[\"stdout\"])\n ),\n \"\"\n)\n\n"}, {"name": "images", "description": "

Any images produced by the code blocks.

", "definition": "flatten(map(\n get(r,\"images\",[]),\n r,\n code_result\n))"}, {"name": "show_images", "description": "

Show the images produced by the code.

The name of the test, shown to the student above any feedback.
The proportion of the credit available for the part to award if this test is passed.
The code to run.

", "input_type": "code", "default_value": "[\n [\"Test 1\", 1, \"True\"]\n]", "evaluate": true}, {"name": "validation_tests", "label": "Validation tests", "help_url": "", "hint": "

A list of tests used to validate that the student's code is acceptable.
Each item is a list with two string values:

A name which will be shown to the student if the test fails.
The code to run.