{"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":45881,"title":"Reindex a vector (★★)","description":"(copy of Prob. 676)\r\n\r\nYou are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero. \r\n\r\nFor example:\r\n\r\n  N = [1 3 2 7];\r\n  IDX= [2 3 4 6];\r\n\r\nthen \r\n  \r\n  y_correct = [0 1 3 2 0 7];\r\n\r\nN(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...\r\n\r\nIf N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.","description_html":"\u003cp\u003e(copy of Prob. 676)\u003c/p\u003e\u003cp\u003eYou are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero.\u003c/p\u003e\u003cp\u003eFor example:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003eN = [1 3 2 7];\r\nIDX= [2 3 4 6];\r\n\u003c/pre\u003e\u003cp\u003ethen\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ey_correct = [0 1 3 2 0 7];\r\n\u003c/pre\u003e\u003cp\u003eN(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...\u003c/p\u003e\u003cp\u003eIf N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.\u003c/p\u003e","function_template":"function y = reindex_a_vector(N,IDX)\r\n  y = N;\r\nend","test_suite":"%%\r\nN = [1 3 2 7];\r\nIDX= [2 3 4 6];\r\ny_correct = [0 1 3 2 0 7];\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n%%\r\nN=[ -1 0 4 2];\r\nIDX=[3 8 1 6];\r\ny_correct = [4 0 -1 0 0 2 0 0];\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n%%\r\nN=[-1 0 4 2]';\r\nIDX=[3 8 1 6];\r\ny_correct = [4 0 -1 0 0 2 0 0]';\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n%%\r\nN=[1 2 3 4 5 6 7 8 9 10];\r\nIDX=[3 4 5 6 7 8 9 10 11 13];\r\ny_correct=[0 0 1 2 3 4 5 6 7 8 9 0 10];\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":428668,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":58,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2020-06-10T19:55:20.000Z","updated_at":"2026-05-30T16:10:39.000Z","published_at":"2020-06-10T19:55:20.000Z","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\u003e(copy of Prob. 676)\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\u003eYou are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero.\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\u003eFor example:\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 = [1 3 2 7];\\nIDX= [2 3 4 6];]]\u003e\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\u003ethen\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[y_correct = [0 1 3 2 0 7];]]\u003e\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\u003eN(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...\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\u003eIf N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.\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":45881,"title":"Reindex a vector (★★)","description":"(copy of Prob. 676)\r\n\r\nYou are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero. \r\n\r\nFor example:\r\n\r\n  N = [1 3 2 7];\r\n  IDX= [2 3 4 6];\r\n\r\nthen \r\n  \r\n  y_correct = [0 1 3 2 0 7];\r\n\r\nN(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...\r\n\r\nIf N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.","description_html":"\u003cp\u003e(copy of Prob. 676)\u003c/p\u003e\u003cp\u003eYou are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero.\u003c/p\u003e\u003cp\u003eFor example:\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003eN = [1 3 2 7];\r\nIDX= [2 3 4 6];\r\n\u003c/pre\u003e\u003cp\u003ethen\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003ey_correct = [0 1 3 2 0 7];\r\n\u003c/pre\u003e\u003cp\u003eN(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...\u003c/p\u003e\u003cp\u003eIf N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.\u003c/p\u003e","function_template":"function y = reindex_a_vector(N,IDX)\r\n  y = N;\r\nend","test_suite":"%%\r\nN = [1 3 2 7];\r\nIDX= [2 3 4 6];\r\ny_correct = [0 1 3 2 0 7];\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n%%\r\nN=[ -1 0 4 2];\r\nIDX=[3 8 1 6];\r\ny_correct = [4 0 -1 0 0 2 0 0];\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n%%\r\nN=[-1 0 4 2]';\r\nIDX=[3 8 1 6];\r\ny_correct = [4 0 -1 0 0 2 0 0]';\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n%%\r\nN=[1 2 3 4 5 6 7 8 9 10];\r\nIDX=[3 4 5 6 7 8 9 10 11 13];\r\ny_correct=[0 0 1 2 3 4 5 6 7 8 9 0 10];\r\nassert(isequal(reindex_a_vector(N,IDX),y_correct))\r\n","published":true,"deleted":false,"likes_count":0,"comments_count":0,"created_by":428668,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":58,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":1,"created_at":"2020-06-10T19:55:20.000Z","updated_at":"2026-05-30T16:10:39.000Z","published_at":"2020-06-10T19:55:20.000Z","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\u003e(copy of Prob. 676)\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\u003eYou are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place the numerical values in a vector N in the output vector y at indices IDX. All other values in the output vector should be zero.\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\u003eFor example:\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 = [1 3 2 7];\\nIDX= [2 3 4 6];]]\u003e\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\u003ethen\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[y_correct = [0 1 3 2 0 7];]]\u003e\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\u003eN(1) goes into y at IDX(1). N(2) goes into y at IDX(2), and so on...\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\u003eIf N is a row vector, your output should be a row vector. If N is a column vector, your output should be a column vector.\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\"}]}"}],"errors":[],"facets":[[],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"vector indexing\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}