{"id":5816,"date":"2015-01-30T09:00:41","date_gmt":"2015-01-30T14:00:41","guid":{"rendered":"https:\/\/blogs.mathworks.com\/pick\/?p=5816"},"modified":"2015-01-29T00:03:41","modified_gmt":"2015-01-29T05:03:41","slug":"fast-programmatic-string-search-in-matlab-files","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/pick\/2015\/01\/30\/fast-programmatic-string-search-in-matlab-files\/","title":{"rendered":"Fast, programmatic string search in MATLAB files"},"content":{"rendered":"
\r\n

Jiro<\/a>'s pick this week is findInM<\/tt><\/a> by our very own Brett Shoelson<\/a>.\r\n <\/p>\r\n

If you know Brett, which you probably do if you've spent any time on MATLAB Central, you know about all the useful File Exchange entries<\/a> he has contributed. It's no surprise he's ranked number 8. Aside from many of the entries related to image processing, he\r\n has uploaded a number of utility functions, and findInM<\/tt> is a must-have. The title of the File Exchange entry starts with \"FAST, PROGRAMMATIC string searching...\", and that's exactly\r\n what it is. It searches for a string of text in MATLAB files, but it's fast and it's programmatic. There are already a number\r\n of entries in File Exchange that searches for a text within files, including mfilegrep<\/tt><\/a>, mgrep<\/tt><\/a>, and grep<\/tt><\/a>. There is also an interactive way<\/a> of searching from the toolstrip.\r\n <\/p>\r\n

<\/p>\r\n

From the description of Brett's entry, findInM<\/tt> \"can be much faster than any other method [he's] seen.\" The way Brett accomplishes this efficient search is by first creating\r\n an index of the MATLAB files in the folders. This step takes some time, but afterwards, the search happens on the index file\r\n and is very efficient.\r\n <\/p>\r\n

In this example, I first created an index of my \/toolbox folder (and its subfolders) of my MATLAB installation. Then searching\r\n for some text from over 20000 files took less than 10 seconds.\r\n <\/p>

tic\r\ns = findInM('graph theory'<\/span>,'toolbox'<\/span>)\r\ntoc<\/pre>
\r\nSORTED BY DATE, MOST RECENT ON TOP:\r\n\r\ns = \r\n    'C:\\Program Files\\MATLAB\\R2014b\\toolbox\\bioinfo\\bioinfo\\Contents.m'\r\n    'C:\\Program Files\\MATLAB\\R2014b\\toolbox\\bioinfo\\biodemos\\graphtheorydemo.m'\r\n    'C:\\Program Files\\MATLAB\\R2014b\\toolbox\\matlab\\sparfun\\Contents.m'\r\n    'C:\\Program Files\\MATLAB\\R2014b\\toolbox\\matlab\\sparfun\\gplot.m'\r\n    'C:\\Program Files\\MATLAB\\R2014b\\toolbox\\bioinfo\\graphtheory\\Contents.m'\r\nElapsed time is 8.334972 seconds.\r\n<\/pre>
As a comparison, the interactive \"Find Files\" tool in MATLAB took over 5 minutes to do the same search.<\/p>\r\n   
Thanks for this great tool, Brett! I do have a couple of suggestions for improvement.<\/p>\r\n   
\r\n