How do I remove redundant commas when writing a txt-file from a table?
10 views (last 30 days)
Show older comments
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
0 Comments
Accepted Answer
Image Analyst
on 28 Jan 2020
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);
3 Comments
Image Analyst
on 28 Jan 2020
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.
More Answers (1)
Stephen23
on 28 Jan 2020
Edited: Stephen23
on 28 Jan 2020
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
0 Comments
See Also
Categories
Find more on Low-Level File I/O in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!