MATLAB: Storing variables from an array loop

arrayloopmatrix

Hello,
I'm coding to import several .txt files in matlab and create as many matrix as the number of file. I created the basic loop but I get stuck when it comes to store my dataArray without keeping overwriting it during the loop.
Here the code that I'm trying to work on to obtain new matrix in the workspace for each loop.
delimiter = '\t';
startRow = 2;
formatSpec = '%f%f%f%f%f%f%[^\n\r]';
for k = 1:3
  % Read the file.
  textFileName = ['SJ' num2str(k) '.txt'];
  if exist(textFileName, 'file')
    fid = fopen(textFileName, 'rt');
                  dataArray = textscan(fid, formatSpec, 'Delimiter', delimiter, 'EmptyValue' ,NaN,'HeaderLines' ,startRow-1, 'ReturnOnError', false);
          fclose(fid);
    else
      fprintf('File %s does not exist.\n', textFileName);
      end
      %Create matrix
      GRFdata = [dataArray{1:end-1}];
end
The issue is that GRFdata keeps overwriting whilst I would obtain GRFdata1, GRFdata2, etc.
Anyone could point me out the right way to proceed, please? Thanks

Best Answer

While you can dynamically create variable names on the fly, it's almost never a good idea. You lose syntax checking, compiler optimisation, ease of debugging, ease of understanding the code, etc.
The best way is to store your various matrices in a cell array:
GRFdata{k} = [dataArray{1:end-1}];
Referring to these matrices afterward is simply:
m = GRFdata{n}; %replace n by the index of the matrix you want to use
If you really want to use different variable names, use eval:
eval(sprintf('GRFdata%d = [dataArray{1:end-1}]', k)); %eugh!

Accessing these matrices is then:
m = eval(sprintf('GRFdata%d', n)); %eugh!
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