Concatenating 'mat' files into a single file

Hi. I have 6 mat files with file names A,B,C,D,E,F each of size 1X36. Now I want to concatenate all this mat files(order same as above) in to new mat file that should be of size 1X216. Please help me in this regard...

Thanks,

srikanth

[Jos (10584)]

I think you are confusing mat files and variables ...

[srikanth]

no i mean '.mat' files. File names are A.mat,B.mat,C.mat,D.mat,E.mat,F.mat Each file contains some image information and of size {1x36} . Now i want to club all of them into single .mat file and make it as {1x216}. [ i.e 36*6=216]

[José-Luis]

Then you need to load them, concatenate the variables you want and save the result. You cannot simply concatenate mat files.

Answer 1

[Jan]

The size of a MAT file is not exactly correlated to the size of the included data, because MAT files can be compressed and they have a header. Therefore it is unlikely, that joining the contents of 6 Matlab files leads to a MAT file, whose size is the sum of the single files. And concatenating the files directly will not work also.

I assume Jos is right: The size of MAT files is measured in Bytes, while an expression like "{1x36}" implies, that you are talking of a vector. Do you mean, that the contents of the MAT files are [1x36] double vectors?

FileList = {'A', 'B', 'C', 'D', 'E', 'F'};
Value = [];
for iFile = 1:numel(FileList)
  Data  = load([FileList{iFile}, '.mat']);
  Field = struct2cell(Data);
  if length(Field) ~= 1
    error('Unexpected contents of [%s]', FileList{iFile});
  end
  Value = cat(2, Value, Field{1});
end
save('Joined.mat', 'Value');

If this does not help, please explain, what you actually want to combine.

[Sruthi D]

If the mat files are of differenet dimensions then how to concatenate.

Example: A.mat contains 165x14 , B.mat contains 169x14, C.mat contains 55x13 then how to concatenate them and save in one new .mat file?

[Walter Roberson]

What would you want as the result? A single .mat file with three variables? A single .mat file with a single variable that is a struct with one field per file? A single .mat file with a single variable that is (for example) [A; B; [C, nan(55,1)]] so as to pad C out to 55 x 14 so it could be put at the bottom of A and B ?

[Sruthi D]

I need a single mat file with dimension 389x14

[Walter Roberson]

What do you want as the 14th column for the block that corresponds to C ?

Answer 2

[Thorsten]

First load the file, assuming that each file contains a variable same as its filename, so after load A you have variable A in your workspace

 load A
 load B
 load C
 load D
 load E
 load F

Concatenate

X = [ A  B C D E F];

Save to new mat file

save('X.mat', 'X')