Listing mat files in a directory and checking to see if they have a particular file.

Greetings I have been having a tough time creating a list of files (.mat files) in a directory in a listbox, and then checking to see if they contain a certain variable. I tried using uigetfile() but that hasn't panned out very well.

How do I get a list of files in a directory no matter what type they are and run a test on them to see if they contain a certain variable?

Thank you

Bill

Answer 1

[Fangjun Jiang]

Files=dir(fullfile('MyFolder','*.mat')) will give you a list of .mat files.

Files=dir(fullfile('MyFolder','*.*')) will give you a list of all files and subfolders.

Files is a structure array, check its fieldnames.

Vars=load('MyData.mat') will return Vars as a structure. fieldnames(Vars) gives you all the variable names in the .mat file.

[Louis-Philippe Guinard]

Hello!

Waaaaay late to the party, but if by any chance someone needs this and finds the same error as me (I'm using 2018a BTW) I tried the first line that was suggested, I.E.:

Files = dir(fullfile(MyFolder, '*.mat'));

Fangjun has written the MyFolder between quotes (as in, 'MyFolder' ) but this returned me a 0x1 structure while it should have been a 30x1 structure in my case. The quotes made it so it searched for a folder named MyFolder, while I was already specifying a path prior to this. It then depends if MyFolder is a string name or a variable.

Hope this precision helps! :)

Answer 2

[Walter Roberson]

hasvar = false;
try
  s = whos('VariableYouWant', '-file', TheFileLocation);
  if ~isempty(s); hasvar = true; end
catch
end

[K E]

To search recursively for all files with a mat extension in order to subsequently apply Walter's solution, use getfilenames.m . Just mentioning this in case someone else wants to perform a recursive search for all mat files containing a desired variable.

[Walter Roberson]

A few years after the above comment from K E, MATLAB added the ability to search indefinite number of layers down:

dinfo = dir(fullfile(BaseFolder, '**', '*.mat'));
filenames = fullfile({dinfo.folder}, {dinfo.name});

The folder field returned by dir() was added at the same time,

Answer 3

[William]

You guys are Awesome. One last thing. How do I specify the file location from within the Gui. I would like the user to be able to choose. Can I just use UIgetfile()?

Thanks

[Fangjun Jiang]

uigetdir()

[Walter Roberson]

uigetfile() if you want to choose which individual file to examine for the variable; uigetdir() if you want to choose which directory to examine. You would use uigetdir() together with dir() in order to examine all files in the chosen directory.