{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":44686,"title":"Draw 'J'","description":"Given n as input, generate a n-by-n matrix 'J' using 0 and 1 .\r\n\r\nExample:\r\n\r\n  n=5\r\n  ans=\r\n  [0 0 0 0 1\r\n   0 0 0 0 1\r\n   0 0 0 0 1\r\n   1 0 0 0 1\r\n   1 1 1 1 1]\r\n n=4\r\n  ans=\r\n  [0 0 0 1\r\n   0 0 0 1 \r\n   1 0 0 1\r\n   1 1 1 1]","description_html":"\u003cp\u003eGiven n as input, generate a n-by-n matrix 'J' using 0 and 1 .\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003en=5\r\nans=\r\n[0 0 0 0 1\r\n 0 0 0 0 1\r\n 0 0 0 0 1\r\n 1 0 0 0 1\r\n 1 1 1 1 1]\r\nn=4\r\nans=\r\n[0 0 0 1\r\n 0 0 0 1 \r\n 1 0 0 1\r\n 1 1 1 1]\r\n\u003c/pre\u003e","function_template":"function ans = J(x)\r\n  zeros(x)\r\nend","test_suite":"%%\r\nx = 5;\r\ny_correct = [0 0 0 0 1\r\n   0 0 0 0 1\r\n   0 0 0 0 1\r\n   1 0 0 0 1\r\n   1 1 1 1 1];\r\nassert(isequal(J(x),y_correct))\r\n%%\r\nx = 3;\r\ny_correct = [0 0 1\r\n   1 0 1 \r\n   1 1 1]  \r\nassert(isequal(J(x),y_correct))\r\n%%\r\nx = 4;\r\ny_correct =  [0 0 0 1\r\n   0 0 0 1\r\n   1 0 0 1\r\n   1 1 1 1]  \r\nassert(isequal(J(x),y_correct))\r\n%%\r\nx = 6;\r\ny_correct = ...\r\n  [0 0 0 0 0 1\r\n   0 0 0 0 0 1\r\n   0 0 0 0 0 1\r\n   0 0 0 0 0 1\r\n   1 0 0 0 0 1\r\n   1 1 1 1 1 1];\r\nassert(isequal(J(x),y_correct))\r\n","published":true,"deleted":false,"likes_count":8,"comments_count":2,"created_by":218677,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":1104,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":46,"created_at":"2018-06-12T20:50:35.000Z","updated_at":"2026-05-24T19:49:28.000Z","published_at":"2018-06-12T20:50:35.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eGiven n as input, generate a n-by-n matrix 'J' using 0 and 1 .\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eExample:\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[n=5\\nans=\\n[0 0 0 0 1\\n 0 0 0 0 1\\n 0 0 0 0 1\\n 1 0 0 0 1\\n 1 1 1 1 1]\\nn=4\\nans=\\n[0 0 0 1\\n 0 0 0 1 \\n 1 0 0 1\\n 1 1 1 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an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN.\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre\u003e Input  x =  [  5  17 -20  99  3.4  2  8  -6 ]\r\n Output y is [  5 NaN NaN NaN  3.4  2  8 NaN ]\u003c/pre\u003e","function_template":"function y = cleanUp(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx         = [  5  17 -20  99  3.4  2  8  -6 ];\r\ny_correct = [  5 NaN NaN NaN  3.4  2 8 NaN ];\r\nassert(isequalwithequalnans(cleanUp(x),y_correct))\r\n\r\n%%\r\nx =         [ -2.80  -6.50  -12.60  4.00  2.20   0.20  -10.60  9.00];\r\ny_correct = [   NaN    NaN     NaN  4.00  2.20   0.20     NaN  9.00]\r\nassert(isequalwithequalnans(cleanUp(x),y_correct))\r\n\r\n\r\n","published":true,"deleted":false,"likes_count":73,"comments_count":16,"created_by":1,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":15805,"test_suite_updated_at":"2012-01-18T01:00:19.000Z","rescore_all_solutions":false,"group_id":2,"created_at":"2012-01-18T01:00:19.000Z","updated_at":"2026-05-27T22:04:50.000Z","published_at":"2012-01-18T01:00:19.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eGiven an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eExample:\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[ Input  x =  [  5  17 -20  99  3.4  2  8  -6 ]\\n Output y is [  5 NaN NaN NaN  3.4  2  8 NaN ]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":44686,"title":"Draw 'J'","description":"Given n as input, generate a n-by-n matrix 'J' using 0 and 1 .\r\n\r\nExample:\r\n\r\n  n=5\r\n  ans=\r\n  [0 0 0 0 1\r\n   0 0 0 0 1\r\n   0 0 0 0 1\r\n   1 0 0 0 1\r\n   1 1 1 1 1]\r\n n=4\r\n  ans=\r\n  [0 0 0 1\r\n   0 0 0 1 \r\n   1 0 0 1\r\n   1 1 1 1]","description_html":"\u003cp\u003eGiven n as input, generate a n-by-n matrix 'J' using 0 and 1 .\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003en=5\r\nans=\r\n[0 0 0 0 1\r\n 0 0 0 0 1\r\n 0 0 0 0 1\r\n 1 0 0 0 1\r\n 1 1 1 1 1]\r\nn=4\r\nans=\r\n[0 0 0 1\r\n 0 0 0 1 \r\n 1 0 0 1\r\n 1 1 1 1]\r\n\u003c/pre\u003e","function_template":"function ans = J(x)\r\n  zeros(x)\r\nend","test_suite":"%%\r\nx = 5;\r\ny_correct = [0 0 0 0 1\r\n   0 0 0 0 1\r\n   0 0 0 0 1\r\n   1 0 0 0 1\r\n   1 1 1 1 1];\r\nassert(isequal(J(x),y_correct))\r\n%%\r\nx = 3;\r\ny_correct = [0 0 1\r\n   1 0 1 \r\n   1 1 1]  \r\nassert(isequal(J(x),y_correct))\r\n%%\r\nx = 4;\r\ny_correct =  [0 0 0 1\r\n   0 0 0 1\r\n   1 0 0 1\r\n   1 1 1 1]  \r\nassert(isequal(J(x),y_correct))\r\n%%\r\nx = 6;\r\ny_correct = ...\r\n  [0 0 0 0 0 1\r\n   0 0 0 0 0 1\r\n   0 0 0 0 0 1\r\n   0 0 0 0 0 1\r\n   1 0 0 0 0 1\r\n   1 1 1 1 1 1];\r\nassert(isequal(J(x),y_correct))\r\n","published":true,"deleted":false,"likes_count":8,"comments_count":2,"created_by":218677,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":1104,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":46,"created_at":"2018-06-12T20:50:35.000Z","updated_at":"2026-05-24T19:49:28.000Z","published_at":"2018-06-12T20:50:35.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml 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an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN.\u003c/p\u003e\u003cp\u003eExample:\u003c/p\u003e\u003cpre\u003e Input  x =  [  5  17 -20  99  3.4  2  8  -6 ]\r\n Output y is [  5 NaN NaN NaN  3.4  2  8 NaN ]\u003c/pre\u003e","function_template":"function y = cleanUp(x)\r\n  y = x;\r\nend","test_suite":"%%\r\nx         = [  5  17 -20  99  3.4  2  8  -6 ];\r\ny_correct = [  5 NaN NaN NaN  3.4  2 8 NaN ];\r\nassert(isequalwithequalnans(cleanUp(x),y_correct))\r\n\r\n%%\r\nx =         [ -2.80  -6.50  -12.60  4.00  2.20   0.20  -10.60  9.00];\r\ny_correct = [   NaN    NaN     NaN  4.00  2.20   0.20     NaN  9.00]\r\nassert(isequalwithequalnans(cleanUp(x),y_correct))\r\n\r\n\r\n","published":true,"deleted":false,"likes_count":73,"comments_count":16,"created_by":1,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":15805,"test_suite_updated_at":"2012-01-18T01:00:19.000Z","rescore_all_solutions":false,"group_id":2,"created_at":"2012-01-18T01:00:19.000Z","updated_at":"2026-05-27T22:04:50.000Z","published_at":"2012-01-18T01:00:19.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml 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