How can I create multiple variables for further processing in a for-loop from imported tables?

Hi all,

I am working on improving the efficiency of codes created and have modified the codes from this example for my application: How can I process a sequence of files?

for k = 1:13
  matFileName = sprintf('XXX_#%d.txt', k);
  if exist(matFileName, 'file')
    Table(k) = readtable(matFileName); % error here
                % without error: Table = readtable(matFileName);
                % save(['FileName' num2str(k)],'Table'); % Need to use a second loop to load the mat-files
  else
    fprintf('File %s does not exist.\n', matFileName);
    end
end

How can I create workspace variables from these imported tables for further processing? This error was shown "Subscripting a table using linear indexing (one subscript) or multidimensional indexing (three or more subscripts) is not supported. Use a row subscript and a variable subscript."

I have attempted to first save the imported tables and then load the mat.file using another for-loop. Is there a direct way of creating workspace variables from these imported tables in one single for-loop?

Thank you for your support.

[Stephen23]

Better to read the MATLAB documentation:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

Notice how they documentation imports the file data into a cell array. This is what you should do too, because using a cell array is simple and efficient.

Answer 1

[jonas]

You could save the data as a cell array instead, by changing the braces

T{k} = readtable(matFileName);

I would recommend not naming your variable Table, as it's quite similar to the function table

If you want the name of the variable to reflect the file name, then I'd recommend using dynamic field variables

 data.(sprintf('file%d',k)=readtable(matFileName);

which you call by e.g.

data.file1

[Harry Porter]

Hi Jonas and Stephen,

Thanks for your swift comments. I have actually tried that method with both brackets before and I obtained the same error:

      if exist(matFileName, 'file')
    XXX_Table{k}= readtable(matFileName); % Still the same error
                save(['FileName' num2str(k)],'XXX_Table');
    else
    fprintf('File %s does not exist.\n', matFileName);
        end

However, as funny as it might seem, the bug was removed by just re-running the script after clearing all the variables in the Workspace and the Command Window. So it is working now! Thank you for your feedback :)

[Stephen23]

@Harry Porter: that is one reason to avoid writing scripts: functions have independent workspaces.