How to copy data from multiple .mat files into single .mat file?

I have multiple .mat files which contain pixel values of images. each mat file has different number of data.. how can i copy or load all of data from multiple .mat files into a single .mat file?

[Dana]

The easiest way to do this depends on how many mat files there are, how many variables are in each mat file, whether you know the variable names in each file already, and whether variables in different mat files have the same name. Can you elaborate on your problem a bit more?

Answer 1

[Sindar]

Assuming absolutely nothing about your data, this should dump the saved data into a single matfile (one variable per loaded file)

% list files to draw from
matfile_names = {'mat1.mat';'matb.mat';'frog'};
% remove extension, clear duplicates
matfile_names_stripped = unique(strrep(matfile_names,'.mat',''));
% create valid-variable-name versions
matfile_names_valid_variable = genvarname(matfile_names_stripped);
% prepare an empty structure
all_data = struct();
% for each file...
for ind=1:length(matfile_names_stripped)
    % load the data into a field of all_data corresponding to the filename
    try
        all_data.(matfile_names_valid_variable{ind}) = load([matfile_names_stripped '.mat']);
    catch ME
        all_data.(matfile_names_valid_variable{ind}) = struct();
    end
end
% save the fields of all_data to a new matfile
save('all_data.mat','-struct','all_data');
% version for larger data
% save('all_data.mat','-struct','all_data','-v7.3');