converting a.mat of different folder to one csv file.

I want to convert my mat-files to CSV. I have 20 mat-files. They are all in the same directory but in different 20 folder kept in paralle , so I want to convert all the .mat file of every folder to one CSV-file and they end with .mat How can I make a loop that takes the 20 .mat file from different folder and convert the mat file into CSV? I have tried this but it is not working , Any help or suggestion is welcomed.

Answer 1

[Walter Roberson]

projectdir = 'c:\parent\directory\of\all\folders';
foldinfo = dir(projectdir);
foldinfo(~[foldinfo.isdir]) = [];  %eliminate non-folders
foldinfo(ismember({foldinfo.name}, {'.', '..'}) = [];   %eliminate . and ..
foldnames = fullfile(projectdir, {foldinfo.name});

overall_content = [];
looking_for_first = true;

for foldidx = 1 : length(foldnames)
  thisfolder = foldnames{foldidx};
  dinfo = dir( fullfile(thisfolder, '*.mat') );
  matfilenames = fullfile(thisfolder, {dinfo.name});

    for fileidx = 1 : length(matfilenames)
      thisfile = matfilenames{fileidx};
      try
        this_content = load(thisfile);
        varnames = fieldnames(this_content);
        if ~isempty(varnames)
          firstvar = varnames{1};
          content = this_content.(firstvar);
          if looking_for_first
            overall_content = content;
            looking_for_first = false;
          else
            overall_content = [overall_content; content];
          end
        end
      catch
      end
    end   %fileidx

end  %foldidx

if isempty(overall_content)
  fprintf('No usableable .mat files found\n');
else

   csvwrite('OutputFile.csv', overall_content);

 end

This code assumes that it is the first variable in each file that is to be written, and that the way the content is to be written is to place it all in rows one after the other.