// Numbas version: exam_results_page_options {"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.

", "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}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Get the first item in a list", "tags": [], "metadata": {"description": "

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.

", "rulesets": {}, "extensions": ["programming"], "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": "

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", "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}]}]}], "contributors": [{"name": "Christian Lawson-Perfect", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/7/"}]}