How do I remove redundant commas when writing a txt-file from a table?

I created a txt-file from a table (139x39) which contains some blanks. The data is separated by commas as delimiter. Unfortunately in the resulting file, commas also separate the blanks:

Raw Data,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
"Friday, Dec 05, 2019,17:00:28",,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
191205.txt,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
95,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
0,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
16,16,16,1,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16
CPS,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Time,7Li,31P,39K,43Ca,44Ca,45Sc,47Ti,55Mn,77ArCl,82Se,83Kr,85Rb,88Sr,89Y,90Zr,93Nb,133Cs,137Ba,139La,140Ce,141Pr,146Nd,147Sm,153Eu,159Tb,160Gd,163Dy,165Ho,166Er,169Tm,172Yb,175Lu,178Hf,181Ta,182W,208Pb,232Th,238U
0,0,1300,1900,0,200,0,0,400,0,750,700,100,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
%underneath this are another 100 rows with data in the same format as the previous row

Ideally, the content of the file should look like this - any idea how to do this?

Also if someone knows a trick on how to remove the double-quotes in line 2, that would be much appreciated.

Raw Data
Friday, Dec 05, 2019,17:00:28
191205.txt
95
0
16,16,16,1,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16
CPS
Time,7Li,31P,39K,43Ca,44Ca,45Sc,47Ti,55Mn,77ArCl,82Se,83Kr,85Rb,88Sr,89Y,90Zr,93Nb,133Cs,137Ba,139La,140Ce,141Pr,146Nd,147Sm,153Eu,159Tb,160Gd,163Dy,165Ho,166Er,169Tm,172Yb,175Lu,178Hf,181Ta,182W,208Pb,232Th,238U
0,0,1300,1900,0,200,0,0,400,0,750,700,100,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0

Answer 1

[Image Analyst]

You could read in the file and use strrep() to replace each ,, with , until there are no ,, left. Basically (untested)

fid = fopen(filename, 'rt');
fidOut = fopen(outputFileName, 'wt')
textLine = fgetl(fid);
while ischar(textLine)
    while contains(textLine, ',,')
        textLine = strrep(textLine, ',,', ',');
    end
    % Now write out
    fprintf(fidOut, '%s\n', textLine);
    % Now read in the next line.
    textLine = fgetl(fid);
end
fclose(fid);
fclose(fidOut);

[Jule]

Thanks but something does not seem to work with the fopen function, I get the following error message:

Error using fopen
The file mode for fopen can not contain modes other than r, w, a, +, b, A, W or t.

I tried changing it to just r or t, but that does not work either.

[Jule]

Ah, there was an accidental additional space in 'rt ' - it works with 'rt'.

This works except for the last comma in the row, thanks!!

[Image Analyst]

You can get rid of trailing comma like this

if endsWith(textLine, ',')
     % textLine ends with a comma.  Strip it off.
     textLine = textLine(1:end-1);
end

You might look at Stephen's code. It's more compact, though more cryptic if you don't know how to construct regular expressions.

Answer 2

[Stephen23]

Regular expressions make this easy (removes all trailing commas, removes the double quotes, and leaves the newlines unchanged):

str = fileread('test.txt')
str = regexprep(str,{',+(\s*\n)','"([^\n"]+)"'},'$1')
[fid,msg] = fopen('test_new.txt','w');
assert(fid>=3,msg)
fprintf(fid,'%s',str)
fclose(fid);

Giving:

Raw Data
Friday, Dec 05, 2019,17:00:28
191205.txt
95
0
16,16,16,1,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16,16
CPS
Time,7Li,31P,39K,43Ca,44Ca,45Sc,47Ti,55Mn,77ArCl,82Se,83Kr,85Rb,88Sr,89Y,90Zr,93Nb,133Cs,137Ba,139La,140Ce,141Pr,146Nd,147Sm,153Eu,159Tb,160Gd,163Dy,165Ho,166Er,1
69Tm,172Yb,175Lu,178Hf,181Ta,182W,208Pb,232Th,238U
0,0,1300,1900,0,200,0,0,400,0,750,700,100,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0