print a cell array as .txt in Matlab

Question

I have a cell array that needs to be printed in a .txt file according to a specific format. I have tried some of the online help (including matlab central dlmcell but even that is not giving me the desired answer. Delimiter is \t.

cellarray = { ...
        'AAPL' '2/20/2011' 100.5 
        'MSFT' '2/15/2011' 43.4551
            } ;

The output should be in a .txt file with the following format: (using tab delimiter)

"AAPL"    "2/20/2011"    100.5
"MSFT"    "2/15/2011"    43.4551

The cell will have minimum of 8000 rows and a maximum of 15000. No rows would have empty columns. Is a vectorized solution possible? Shall appreciate your help.

Answer 1

The following will work for your example:

C = cellarray.';
fid = fopen('file.dlm', 'wt');
fprintf(fid, '"%s"\t"%s"\t%g\n', C{:});
fclose(fid);

MATLAB reuses the formatting string until it runs out of inputs. In principle, you could construct the formatting string first:

fstr = '';
for ic = 1:size(cellarray,2)
   switch class(cellarray{1,ic})
       case 'char'
           fstr = [fstr '"%s"'];
       otherwise
           % Assume numeric
           fstr = [fstr '%g'];
   end
   if ic < size(cellarray,2), fstr = [fstr '\t']; else fstr = [fstr '\n']; end
end

Then

C = cellarray.';
fid = fopen('file.dlm', 'wt');
fprintf(fid, fstr, C{:});
fclose(fid);

Answer 2

I often use combination of DLMWRITE and XLSWRITE. DLMWRITE is used to make a text file, so XLSWRITE will not generate the file in Excel format, but will leave it as a text.

filename = 'file.txt';
dlmwrite(filename, 1)
xlswrite(filename, cellarray)

Note that on OS where COM is not available (like Linux) XLSWRITE write to text, so you don't need the call to DLMWRITE.

---

UPDATE

This method does not work anymore with the latest versions of MATLAB (since probably R2012b). xlswrite always writes to Excel-formatted file.

However, since R2013b MATLAB introduced TABLES, and WRITETABLE function works great if cell array can be converted to a table (check CELL2TABLE function).