Can you use DIR to list files in subfolders ?

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John on 12 Mar 2012
Commented: Jorge Castillo on 9 Jan 2020
Would somebody be able to advise me on how to use DIR to find the dates that each file was last modified with a .mat extension in all sub folders in current directory?
This code does not look in sub directories. Also how to you specify the .mat extension.
files = dir(datenum)
Many thanks

Accepted Answer

Walter Roberson
Walter Roberson on 12 Mar 2012
You cannot do that in a single dir() call.
You need one dir() call on the current folder, and you look at the isdir() field of the results to see which names correspond to folders:
dirinfo = dir();
dirinfo(~[dirinfo.isdir]) = []; %remove non-directories
Then do a step to remove the folder names "." and ".." so you do not infinite loop.
Then you loop over all those names and look inside each of the designated folders:
subdirinfo = cell(length(dirinfo));
for K = 1 : length(dirinfo)
thisdir = dirinfo(K).name;
subdirinfo{K} = dir(fullfile(thisdir, '*.mat'));
Now subdirinfo{K} is the structure of information about the .mat files in the directory dirinfo(K).name
Walter Roberson
Walter Roberson on 10 Aug 2016
Only if you understand that assigning NULL means to delete them.

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More Answers (6)

Jan on 3 May 2017
In modern Matlab versions:
files = dir('D:\Data\**\*.mat')
Jorge Castillo
Jorge Castillo on 9 Jan 2020
For those using a previous version of R2016b, I propose to download the subdir function from here. Then create a script with the foll. lines and run it (F5):
a = mfilename('fullpath');
b = mfilename();
a = strrep(a,b,'');
addpath(a) % Adding the script current path
spath= 'D:\titi'; % Directory where the files are placed
list_struc = subdir(fullfile(spath, '*.c')); %Result : a List (as structure)...
% having the fullfile names of the desired file (eg. *.c)

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Walter Roberson
Walter Roberson on 13 Mar 2012
filetofind = 'data.mat';
dirinfo = dir();
dirinfo(~[dirinfo.isdir]) = []; %remove non-directories
tf = ismember( {}, {'.', '..'});
dirinfo(tf) = []; %remove current and parent directory.
numsubdir = length(dirinfo);
lastmod = inf * ones(numsubdir,1);
for K = 1 : numsubdir
subdirinfo = dir(fullfile(dirinfo(K).name, filetofind));
if ~isempty(subdirinfo)
lastmod(K) = subdirinfo(1).datenum;
[sortedmod, sortorder] = sort(lastmod);
sordorder(~isfinite(sortedmod)) = []; %directories without data.mat
for K = 1 : length(sortorder)
thisdirnum = sortorder(K);
thisoutname = sprintf('file%d.xls', K);
%copy from the subdirectory in to a sequentially named .xls file
copy( fullfile( dirinfo(thisdirnum).name, filetofind ), thisoutname );
John on 22 May 2012
Thanks very much for your help. I got it working.

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Frederic Moisy
Frederic Moisy on 12 Mar 2012
  1 Comment
John on 12 Mar 2012
Hello Frederic,
Would you mind helping me code this for my application. I've been trying for hours with no luck.
Thank you

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Luke Melo
Luke Melo on 25 Nov 2019
Found this article very useful. Here's the code I use to select a folder from a dialogue window and find all the files, png here for example, within all subdirectories:
path = uigetdir('/Users/user/')
files = dir(fullfile(path,'**','*.png'));
Walter Roberson
Walter Roberson on 25 Nov 2019
The line I show with fullfile() is an extra step to extract fully qualified file names from the structure that is returned by dir() . When the '**' wildcard is used with dir() each different result might come from a different directory, and the same name might show up with respect to different directories, so it becomes important to put together the folder name and file name.

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Matthias on 3 May 2017
Edited: Matthias on 3 May 2017
Although this does not answer the whole question it adresses the title (which is what I was looking for): to get a list of all(!) subfolders below a specified folder or drive one could use the dos command like this:
[s, r] = dos('dir X:\folder\ /s /b /A:D');
folders = regexpi(r, '\n', 'split')';
Using the /s option the dos dir command will go down all the way (no option to specifiy a max recursion depth here - beware of long execution times!), with attribute D (/A:D) only directories will be returned and finally the /b option gives us a nice plain list (as a very long string) that can be easily split for further use.
[s, r] = dos('dir X:\folder\*.mat /s /b');
matFiles = regexpi(r, '\n', 'split')';
will obviously give you the list of all .mat files, the date of these can easily be obtained with another dir() call:
l = cellfun(@dir, matFiles);
changeTimes = [l.datenum]';

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Ba Mo
Ba Mo on 21 Apr 2019
as lots of users reported above, new versions of matlab support the following command dir('**/*.mat');
However, old versions of matlab don't support this
instead of writing a large code, inspect the structure field "isfield" and so on, you could just easily ask DOS (or the command prompt) to do it for you. the output from MS-DOS isn't formatted, so you need to split the one block string to separate lines
newline = char(10); %char(10) is the character for line-break, or "enter"
[~,all_mats] = system('dir /s /b *.mat'); %you can also simply write: !dir /s /b *.mat
all_mats = strsplit(all_mats,newline)';
all_mats(cellfun(@isempty,all_mats))=[]; %the last entry/line might be an empty cell. delete it.


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