// Numbas version: exam_results_page_options
{"name": "Sort a list of lists by a particular key", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"name": "Sort a list of lists by a particular key", "tags": [], "metadata": {"description": "<p><strong>Obosolete:</strong> there's now a built-in function <code>sort_by</code>.</p>\n<p>Defines a custom function sort_by to sort a list of lists by the elements at the given index.</p>\n<p>You could do a similar thing to sort lists of dictionaries.</p>", "licence": "Creative Commons Attribution 4.0 International"}, "statement": "<p>{table(zip(names,order),['Name','Position'])}</p>\n<p>The order is {join(sorted,', ')}</p>", "advice": "", "rulesets": {}, "extensions": [], "variables": {"names": {"name": "names", "group": "Ungrouped variables", "definition": "[\"A\",\"B\",\"C\",\"D\",\"E\",\"F\"]", "description": "<p>The list that we want to sort.</p>", "templateType": "anything"}, "order": {"name": "order", "group": "Ungrouped variables", "definition": "shuffle(1..len(names))", "description": "<p>The values that will be used to order the corresponding elements of names.</p>", "templateType": "anything"}, "sorted": {"name": "sorted", "group": "Ungrouped variables", "definition": "map(\n  x[0],\n  x,\n  sort_by(1,zip(names,order))\n)", "description": "<ol>\n<li>Zip names and order together, to form a list of items of the form <code>[name,order]</code></li>\n<li>Sort the zipped list by item 1, using the custom function <code>sort_by</code>.</li>\n<li>Get just the name for each item in the sorted list</li>\n</ol>", "templateType": "anything"}}, "variablesTest": {"condition": "", "maxRuns": 100}, "ungrouped_variables": ["names", "order", "sorted"], "variable_groups": [], "functions": {"sort_by": {"parameters": [["index", "number"], ["list", "list"]], "type": "list", "language": "javascript", "definition": "return list.slice().sort(function(a,b) {\n  a = a[index];\n  b = b[index];\n  return a > b ? 1 : a < b ? -1 : 0;\n})"}}, "preamble": {"js": "", "css": ""}, "parts": [], "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/"}]}