{"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":1383,"title":"Count letters occurence in text, specific to words with a given length.","description":"Build a function with two input arguments: a string and a word length (number of letters), that outputs a vector of counts of the 26 letters of the alphabet, specific to words with a given length.\r\n\r\n* Case insensitive.\r\n* Words contain only letters a-zA-Z, but the string can contain punctuation.\r\n\r\n*Example*\r\n\r\n \u003e\u003e txt = 'Hello World, from MATLAB' ;\r\n \u003e\u003e nl  = 5 ;                              % Number of letters.\r\n \u003e\u003e nlWords_getCounts(txt, nl)\r\n ans = \r\n     0  0  0  1  1  0  0  1  0  0  0  3  0  0  2  0  0  1  0  0  0  0  1  0  0  0\r\n\r\nhere, two 5 letters words are found: 'Hello' and 'World'. The output vector is the count of letters (1 to 26) in these two words taken together. For example, letter 12 is 'l/L' and we see that it appears 3 times, hence the count of 3.\r\n ","description_html":"\u003cp\u003eBuild a function with two input arguments: a string and a word length (number of letters), that outputs a vector of counts of the 26 letters of the alphabet, specific to words with a given length.\u003c/p\u003e\u003cul\u003e\u003cli\u003eCase insensitive.\u003c/li\u003e\u003cli\u003eWords contain only letters a-zA-Z, but the string can contain punctuation.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003e\u003cb\u003eExample\u003c/b\u003e\u003c/p\u003e\u003cpre\u003e \u003e\u003e txt = 'Hello World, from MATLAB' ;\r\n \u003e\u003e nl  = 5 ;                              % Number of letters.\r\n \u003e\u003e nlWords_getCounts(txt, nl)\r\n ans = \r\n     0  0  0  1  1  0  0  1  0  0  0  3  0  0  2  0  0  1  0  0  0  0  1  0  0  0\u003c/pre\u003e\u003cp\u003ehere, two 5 letters words are found: 'Hello' and 'World'. The output vector is the count of letters (1 to 26) in these two words taken together. For example, letter 12 is 'l/L' and we see that it appears 3 times, hence the count of 3.\u003c/p\u003e","function_template":"function counts = nlWords_getCounts(txt, nl)\r\n  counts = 0 ;\r\nend","test_suite":"%%\r\ntxt = 'Hello World, from MATLAB' ;\r\nnl  = 5 ;\r\ncounts_correct = [0 0 0 1 1 0 0 1 0 0 0 3 0 0 2 0 0 1 0 0 0 0 1 0 0 0];\r\nassert(isequal(nlWords_getCounts(txt, nl),counts_correct))\r\n\r\n%%\r\ntxt = 'UPPER converts any lowercase characters in the string str to the corresponding uppercase characters and leaves all other characters unchanged.'\r\nnl  = 9 ;\r\ncounts_correct = [3 0 3 1 5 0 1 1 0 0 0 1 0 2 1 2 0 2 2 0 2 0 1 0 0 0];\r\nassert(isequal(nlWords_getCounts(txt, nl),counts_correct))\r\n\r\n%%\r\ntxt = 'UPPER converts any lowercase characters in the string str to the corresponding uppercase characters and leaves all other characters unchanged.'\r\nnl  = 10 ;\r\ncounts_correct = [6 0 6 0 3 0 0 3 0 0 0 0 0 0 0 0 0 6 3 3 0 0 0 0 0 0];\r\nassert(isequal(nlWords_getCounts(txt, nl),counts_correct))\r\n","published":true,"deleted":false,"likes_count":4,"comments_count":0,"created_by":9862,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":202,"test_suite_updated_at":"2013-03-25T03:27:53.000Z","rescore_all_solutions":false,"group_id":28,"created_at":"2013-03-25T03:08:33.000Z","updated_at":"2026-05-06T03:48:20.000Z","published_at":"2013-03-25T03:27:53.000Z","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\u003eBuild a function with two input arguments: a string and a word length (number of letters), that outputs a vector of counts of the 26 letters of the alphabet, specific to words with a given length.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eCase insensitive.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWords contain only letters a-zA-Z, but the string can contain punctuation.\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\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[ \u003e\u003e txt = 'Hello World, from MATLAB' ;\\n \u003e\u003e nl  = 5 ;                              % Number of letters.\\n \u003e\u003e nlWords_getCounts(txt, nl)\\n ans = \\n     0  0  0  1  1  0  0  1  0  0  0  3  0  0  2  0  0  1  0  0  0  0  1  0  0  0]]\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\u003ehere, two 5 letters words are found: 'Hello' and 'World'. The output vector is the count of letters (1 to 26) in these two words taken together. For example, letter 12 is 'l/L' and we see that it appears 3 times, hence the count of 3.\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":1383,"title":"Count letters occurence in text, specific to words with a given length.","description":"Build a function with two input arguments: a string and a word length (number of letters), that outputs a vector of counts of the 26 letters of the alphabet, specific to words with a given length.\r\n\r\n* Case insensitive.\r\n* Words contain only letters a-zA-Z, but the string can contain punctuation.\r\n\r\n*Example*\r\n\r\n \u003e\u003e txt = 'Hello World, from MATLAB' ;\r\n \u003e\u003e nl  = 5 ;                              % Number of letters.\r\n \u003e\u003e nlWords_getCounts(txt, nl)\r\n ans = \r\n     0  0  0  1  1  0  0  1  0  0  0  3  0  0  2  0  0  1  0  0  0  0  1  0  0  0\r\n\r\nhere, two 5 letters words are found: 'Hello' and 'World'. The output vector is the count of letters (1 to 26) in these two words taken together. For example, letter 12 is 'l/L' and we see that it appears 3 times, hence the count of 3.\r\n ","description_html":"\u003cp\u003eBuild a function with two input arguments: a string and a word length (number of letters), that outputs a vector of counts of the 26 letters of the alphabet, specific to words with a given length.\u003c/p\u003e\u003cul\u003e\u003cli\u003eCase insensitive.\u003c/li\u003e\u003cli\u003eWords contain only letters a-zA-Z, but the string can contain punctuation.\u003c/li\u003e\u003c/ul\u003e\u003cp\u003e\u003cb\u003eExample\u003c/b\u003e\u003c/p\u003e\u003cpre\u003e \u003e\u003e txt = 'Hello World, from MATLAB' ;\r\n \u003e\u003e nl  = 5 ;                              % Number of letters.\r\n \u003e\u003e nlWords_getCounts(txt, nl)\r\n ans = \r\n     0  0  0  1  1  0  0  1  0  0  0  3  0  0  2  0  0  1  0  0  0  0  1  0  0  0\u003c/pre\u003e\u003cp\u003ehere, two 5 letters words are found: 'Hello' and 'World'. The output vector is the count of letters (1 to 26) in these two words taken together. For example, letter 12 is 'l/L' and we see that it appears 3 times, hence the count of 3.\u003c/p\u003e","function_template":"function counts = nlWords_getCounts(txt, nl)\r\n  counts = 0 ;\r\nend","test_suite":"%%\r\ntxt = 'Hello World, from MATLAB' ;\r\nnl  = 5 ;\r\ncounts_correct = [0 0 0 1 1 0 0 1 0 0 0 3 0 0 2 0 0 1 0 0 0 0 1 0 0 0];\r\nassert(isequal(nlWords_getCounts(txt, nl),counts_correct))\r\n\r\n%%\r\ntxt = 'UPPER converts any lowercase characters in the string str to the corresponding uppercase characters and leaves all other characters unchanged.'\r\nnl  = 9 ;\r\ncounts_correct = [3 0 3 1 5 0 1 1 0 0 0 1 0 2 1 2 0 2 2 0 2 0 1 0 0 0];\r\nassert(isequal(nlWords_getCounts(txt, nl),counts_correct))\r\n\r\n%%\r\ntxt = 'UPPER converts any lowercase characters in the string str to the corresponding uppercase characters and leaves all other characters unchanged.'\r\nnl  = 10 ;\r\ncounts_correct = [6 0 6 0 3 0 0 3 0 0 0 0 0 0 0 0 0 6 3 3 0 0 0 0 0 0];\r\nassert(isequal(nlWords_getCounts(txt, nl),counts_correct))\r\n","published":true,"deleted":false,"likes_count":4,"comments_count":0,"created_by":9862,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":202,"test_suite_updated_at":"2013-03-25T03:27:53.000Z","rescore_all_solutions":false,"group_id":28,"created_at":"2013-03-25T03:08:33.000Z","updated_at":"2026-05-06T03:48:20.000Z","published_at":"2013-03-25T03:27:53.000Z","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\u003eBuild a function with two input arguments: a string and a word length (number of letters), that outputs a vector of counts of the 26 letters of the alphabet, specific to words with a given length.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eCase insensitive.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"ListParagraph\\\"/\u003e\u003cw:numPr\u003e\u003cw:numId w:val=\\\"1\\\"/\u003e\u003c/w:numPr\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWords contain only letters a-zA-Z, but the string can contain punctuation.\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:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\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[ \u003e\u003e txt = 'Hello World, from MATLAB' ;\\n \u003e\u003e nl  = 5 ;                              % Number of letters.\\n \u003e\u003e nlWords_getCounts(txt, nl)\\n ans = \\n     0  0  0  1  1  0  0  1  0  0  0  3  0  0  2  0  0  1  0  0  0  0  1  0  0  0]]\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\u003ehere, two 5 letters words are found: 'Hello' and 'World'. The output vector is the count of letters (1 to 26) in these two words taken together. For example, letter 12 is 'l/L' and we see that it appears 3 times, hence the count of 3.\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":"Back to Alphabet","count":1,"selected":false},{"value":"Strings II","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"counts\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}