using fullfile when you need to pass a string as an input argument with readable TreatAsEmpty

Hi,

I have a folder of files which have strings as headers and when there are fields which the measuring system could not measure it fills those fields with a string ('UND. -62011'), I have been using

Folder_used = dir('/Users/username/Desktop/data/*.txt');
files = Folder_used;
 for k=1:numel(files)
            data=readtable(files(k).name,'FileType','text',...
'Delimiter','tab','TreatAsEmpty',["UND. -60001","UND. -2011","UND. -62011"]);
%do stuff
end

which works fine. When I want to put this in a standalone app I have a problem. I need to use fullfile to pass the location of the directory and then have the user select the folder, then combine them

i assign the directory as A1 having after having converted it to a string

for k=1:numel(files)
            full_name=fullfile(A1,files(k).name)
            data=readtable(full_name,'FileType','text',...
'Delimiter','tab',...
'TreatAsEmpty',{'UND. -60001','UND. -2011','UND. -62011'});

but get the error

*Error using fullfile (line 51) String input not supported.

Error in tool/rows3d_Callback (line 157) full_name=fullfile(A1,files(k).name)

Error while evaluating UIControl Callback.*||||

Is there a way to use/get around the read table TreatAsEmpty argument with a string input and use fullfile?

Best regards,

Steve

Answer 1

[Jan]

The problem is here:

 i assign the directory as A1 having after having converted it to a string

You did not provide the code you use for this. But the error message is clear: fullfile requires a char vector, not a modern string object.

Folder   = '/Users/username/Desktop/data/';  % As char vector, not as string
FileList = dir(fullfile(Folder, '*.txt'));
for k = 1:numel(FileList)
   File = fullfile(Folder, files(k).name);
   data = readtable(File, 'FileType', 'text', ...
                    'Delimiter','tab','TreatAsEmpty', ...
                    {'UND. -60001', 'UND. -2011', 'UND. -62011'});
   %do stuff
end

In modern Matlab version the folder is replied by dir also. Then this works also:

     File = fullfile(files(k).folder, files(k).name);
 Is there a way to use/get around the read table TreatAsEmpty argument
 with a string input and use fullfile?

Neither readtable nor the 'TreatAsEmpty' argument has been the problem, but exactly as the error message told you, only the input argument of fullfile.