MATLAB: Dir sorts filenames wrong

Question

This is how the files are sorted in the (windows)folder (by name):

Thats also how i want them to to be sorted.

This is how matlab sorts them if i use 'dir':

what can i do?

thanks!

Answer 1

"what can i do?"

If the filenames contain sufficient leading zeros, then split the names using fileparts, then sort the names, e.g.:

S = dir(....);
C = {S.name};
[~,F] = cellfun(@fileparts,C,'uni',0);
[~,X] = sort(F);
C = C(X);

Tested on some sample filenames:

>> C = {'Data2F.Part010.mdf','Data2F.Part003.mdf','Data2F.Part009.mdf','Data2F.mdf'};
>> [~,F] = cellfun(@fileparts,C,'uni',0);
>> [~,X] = sort(F);
>> C = C(X);
>> C{:}
ans = Data2F.mdf
ans = Data2F.Part003.mdf
ans = Data2F.Part009.mdf
ans = Data2F.Part010.mdf

Otherwise you can download my FEX submission natsortfiles and use it to sort the filenames (it splits the file extension for you, and also takes into account any number values in the names):

https://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

The submission includes help and HTML documentation with plenty of examples, you would probably need something a bit like this:

S = dir(....);
C = natsortfiles({S.name});

Note that with either sort or natsortfiles you can obtain the sort indices, to sort the structure with:

S = dir(...);
[~,X] = natsortfiles({S.name}); % or SORT
S = S(X);