When using writetable, I get the error "FILENAME must be a non-empty character vector or string scalar."

What I am trying to do is choose a folder with files in it that contain data, retrieve this data, and save it as a txt file. I am not having any problems with the data itself but rather, naming the text file I am saving the data to. Ideally, I would like to save the text file with the same name as the origional file but I am having trouble doing so. This issue only happens when I am processing more than one file.

I have been working on this issue for a long time and any help would be greatly appreciated.

 Folder = uigetdir; % asks user for a folder

Error using matlab.internal.lang.capability.Capability.require (line 94)
Support for Java user interfaces is required, which is not available on this platform.

Error in uigetdir (line 52)
Capability.require(Capability.Swing);

 FilePattern = fullfile(Folder,'*deer*.dta'); % searches folder for .DTA files with DEER in the name
 Files = dir(FilePattern); % puts files into struct array 

  for n=1:numel(Files)
     File = struct2table(Files); % Takes the file name out of a struct and into a table
     writetable(Deer_Trace_data{n},[ File{n,1} '.txt']); % names and saves file
  end 

Small point but currently, it also saves the filename including its previous extension which is .dta. Ideally, this would be removed but its not a big deal.

Please let me know if you need any more information.

Thanks!

Answer 1

[Image Analyst]

Try this:

Folder = uigetdir; % asks user for a folder
FilePattern = fullfile(Folder,'*deer*.dta'); % searches folder for .DTA files with DEER in the name
%filePattern = fullfile(Folder, '*deer*.txt'); % searches folder for .txt files with DEER in the name
Files = dir(filePattern); % puts files into struct array
for n = 1 : numel(Files)
    % Get input filename.
    fullFileName = fullfile(Files(n).folder, Files(n).name);
    fprintf('Reading "%s".\n', fullFileName);
    % Call your function to read the .dta file and put it into a table variable.
    thisTable = ReadDTAFile(fullFileName);
    Deer_Trace_data{n} = thisTable;
    % Get output filename.  It's the same except the extension is txt instead of dta.
    outputFullFileName = strrep(fullFileName, '.dta', '.txt')
    % Write the table to a text file.
    fprintf('Writing "%s".\n', outputFullFileName);
    writetable(Deer_Trace_data{n}, outputFullFileName);
end

[Alex Garces]

Thank you for the quick response!

Here is the code that ended up working. I ran into some issues trying to replicate your code, but I took parts of it and got it to work!

I guess using a struct as "FILENAME" in writetable is okay and that if you index your file names in a table you might run into some issues.

 Folder = uigetdir; % asks user for a folder
 FilePattern = fullfile(Folder,'*deer*.dta'); % searches folder for .DTA files with DEER in the name
 Files = dir(FilePattern); % puts files into struct array 

  for n=1:numel(Files)
   fullFileName = fullfile(Files(n).folder, Files(n).name); %Gathers the path and file name  
   %%% insert fancy data processing %%%
   outputFullFileName = strrep(Files(n).name, '.DTA','.txt'); % Get output filename.  It's the same except the extension is txt instead of dta.
   writetable(Deer_Trace_data{n}, ['_DEER_Trace',outputFullFileName]);
  end 

Thank you so much, you are a life saver.

[Image Analyst]

Looks like my code, except for having the comments removed and prepending "_DEER_Trace" before the output filename. Generally I (and I think most people) would not recommend removing explanatory comments. Thanks for Accepting the answer.

[Alex Garces]

You are correct that is my fault. The issue was with outputFullFileName in strrep being changed to Files(n).name, that way the entire file path isn't used to name the file. I will include explanatory comments in the future.