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Can you use DIR to list files in subfolders ?

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John
John on 12 Mar 2012
Commented: Jorge Castillo on 9 Jan 2020
Hello,
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

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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'));
end
Now subdirinfo{K} is the structure of information about the .mat files in the directory dirinfo(K).name

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Walter Roberson
Walter Roberson on 8 Aug 2016
dirinfo is a structure array. Picking one field out of a structure array results in structure expansion. Putting [] around the structure expansion results in a vector of the values. So it is like
[dirinfo(1).isdir, dirinfo(2).isdir, dirinfo(3).isdir, ....]
The ~ is logical negation, so ~ of the expression is going to result in true for the places that are not directories. And then that is used as a logical index to select the entries in the structure to delete.
Vids deo
Vids deo on 9 Aug 2016
Hi Walter,
I'm kinda understanding what you're saying. But please clarify if the statement means the following in words - "Assign NULL to the elements of the 'dirinfo' structure array which have '0' or FALSE in the isdir field." --Vidya
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
Jan on 3 May 2017
In modern Matlab versions:
files = dir('D:\Data\**\*.mat')

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Koustubh Shirke
Koustubh Shirke on 14 Aug 2019
Yes , Right it works in 2017a and onwards.
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.name}, {'.', '..'});
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;
end
end
[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 );
end

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John
John on 22 May 2012
Hi Walter,
The variables are vectors of different sizes. The first variable is n X 1 and the the second variable is m x 2. So this means I need two xlswrite() calls. Is this correct? - Do I need two lines for "thisdata =" and "fprint" also?
Thanks for your help
John
filetofind = 'data.mat';
dirinfo = dir();
dirinfo(~[dirinfo.isdir]) = []; %remove non-directories
tf = ismember( {dirinfo.name}, {'.', '..'});
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;
end
end
[sortedmod, sortorder] = sort(lastmod);
sordorder(~isfinite(sortedmod)) = []; %directories without data.mat
vartofind = 'ess_plant_energy_in_total_simu';
vartofind1 = 'sch_cycle';
for K = 1 : length(sortorder)
thisdirnum = sortorder(K);
thisdirname = dirinfo(thisdirnum).name;
thisoutname = sprintf('file%d.xls', K);
try
thisdata = load( fullfile(thisdirname,filetofind), vartofind);
thisdata1 = load( fullfile(thisdirname,filetofind), vartofind1);
xlswrite( thisoutname, thisdata.(vartofind) );
xlswrite( thisoutname, thisdata1.(vartofind1) );
catch
fprintf(2, 'File "%s/%s" does not have variable "%s\n", thisdirname, filetofind, vartofind);
fprintf(2, 'File "%s/%s" does not have variable "%s\n", thisdirname, filetofind, vartofind1);
end
end
Walter Roberson
Walter Roberson on 22 May 2012
You can combine the load() into a single statement:
thisdata = load( fullfile(thisdirname,filetofind), vartofind, vartofind1 );
xlswrite( thisoutname, thisdata.(vartofind) );
xlswrite( thisoutname, thisdata.(vartofind1) );
However, you need to either write to different file names or else use range specifications on the xlswrite() -- otherwise the data from the second xlswrite() will overwrite the first.
John
John on 22 May 2012
Thanks very much for your help. I got it working.
Regards
John

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Frederic Moisy
Frederic Moisy on 12 Mar 2012

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John
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
John

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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'));

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Walter Roberson
Walter Roberson on 25 Nov 2019
We do, though, recommend against using path as a variable name, as path is an important MATLAB function.
Also note that files that results here will be a directory information structure. To get the file names you would use
filenames = fullfile({files.folder}, {files.name});
Luke Melo
Luke Melo on 25 Nov 2019
interesting, I have no issues running the code without the cell {} brackets, but I'm a fan of consistent syntax
also you're right about the variable name path
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
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.
Edit:
[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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Coco
Coco on 19 Jul 2019
Can you please help me with coding to put those files into the new folder?
thank you.
Guillaume
Guillaume on 19 Jul 2019
What files? What new folder?
It doesn't look like your question has much to do with the question being answered here, so please start your own question. Give as many details as possible about what you're trying to do.

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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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