CSV convert will not work with string file name

Hello,

I am writing a GUI to convert parts of .mat files into excel files.

the variables tht are to be converted are stored in a listbox entitled 'listbox2' To clarify where they came from I am trying to put the name of the .mat file on them as a prefix but I cannot seem to get the output files to show up at all.

Worse, this fails to generate any errors. I run the csvwrite command but nothing happens.

Here is the code:

function convert_button_Callback(hObject, eventdata, handles) % hObject handle to convert_button (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)

filelocation = get(handles.MAT_file, 'string');

loadfile =['load ''' filelocation ''''];

eval(loadfile);

%evaluate the sting as if it were a command. See notes on %apostrophies for this one. %eval(['varlist = who(''-file'' , ''' filelocation ''');']);

exportlist = get(handles.listbox2,'string')

%we need to change the directory to the chosen output and after we have %re-loaded the .mat file into the workspace convert the files %The evalin evaluates the expression in 'base' or workspace

for a = 1:length(exportlist) finaltag = strcat(filelocation, exportlist{a})

    outloc = get(handles.CSV_file, 'string');
    cdstring = ['cd(''' outloc ''')'];
    eval(cdstring);
    csvwrite([finaltag,'.csv'],evalin('base',exportlist{a}))
    %Orional code
    %csvwrite([exportlist{a},'.csv'],evalin('base',exportlist{a}))

end

Answer 1

[Walter Roberson]

Your code can be considerably simplified. Yes, I know the below code is much longer, but I added a lot of error checking; the heart of the code is small and efficient.

olddir = cd;
outloc = get(handles.CSV_file, 'string');

try
  cd(outloc);
catch
  error(sprintf('failed to cd to %s', outloc));
end

filelocation= get(handles.MAT_file, 'string');

try  
  S = load(filelocation);
catch
  error(sprintf('failed to load file %s', filelocation));
end

for a = 1:length(exportlist)
  v = exportlist{a};
  if isfield(S, v)
    finaltag = [filelocation, v, '.csv'];
    try
      csvwrite([finaltag,'.csv'],S.(v));
    catch
      warning(sprintf('was unable to write variable %s to file %s', v, finaltag));
    end
  else
    warning(sprintf('input file %s does not contain variable %s, csv not written for variable', filelocation, v))
  end

end

cd(olddir)

Answer 2

[Walter Roberson]

Please strongly avoid using eval()

Your file can be loaded by using command syntax for the load command:

load(filelocation)

where filelocation is a variable.

[William]

for a = 1:length(exportlist)

outloc = get(handles.CSV_file, 'string');

cdstring = ['cd(''' outloc ''')'];

eval(cdstring);

filelocation= get(handles.MAT_file, 'string');

finaltag = strcat(filelocation, exportlist{a})

load(filelocation)

csvwrite([finaltag,'.csv'],evalin('base',exportlist{a}))

end

It still will not give me an error nor will it write to excel.

I am stumped

[Walter Roberson]

Don't use eval for the cd either!

for a = 1:length(exportlist)

olddir = cd;

outloc = get(handles.CSV_file, 'string');

cd(outloc);

filelocation= get(handles.MAT_file, 'string');

finaltag = strcat(filelocation, exportlist{a});

load(filelocation)

csvwrite([finaltag,'.csv'],evalin('base',exportlist{a}))

cd(olddir)

end

Then you are just faced with the question of why you are loading information in to your *current* workspace, but trying to export data from the base workspace. I would suggest that it would probably make more sense to use the form of load() that uses the output argument:

for a = 1:length(exportlist)

olddir = cd;

outloc = get(handles.CSV_file, 'string');

cd(outloc);

filelocation= get(handles.MAT_file, 'string');

finaltag = strcat(filelocation, exportlist{a});

S = load(filelocation);

V = fieldnames(S);

csvwrite([finaltag,'.csv'],S.(V{1});

cd(olddir)

end

The above code assumes that the file you are loading from has only a single variable in it.