How to append data from multiple runs of script without overwriting previous data.

Hi,

My code follows. Everything is correct except that only the value from the last run of the script is saved in the output file. Please can someone help?

The commands commented out also have been tried and do not work. Please help me...

numfilesx = 2
numfilesy = 2

OutputFilePath = 'C:\1Feb19 output';
OutputFilePhase = 'PhaseDiff.csv';

for x = 0:numfilesx
    for y = 0:numfilesy
        myfilename = sprintf("C:\\1Feb19_final\\row%d_%d.csv", y, x);
        PhaseDiff = atan (Y1(1)/Z1(1));
        csvwrite(filenamePhase,PhaseDiff,x,y)
        
        %dlmwrite(filenamePhase,PhaseDiff,'delimiter',' ','roffset',1)
        %filenamePhase = fullfile(OutputFilePath, OutputFilePhase);
        %[fid1, msg] = fopen(filenamePhase, 'wt');
        %if fid1 < 0
        %    error('Could not open file "%s" because "%s"', fid1, msg);
        %end
        %fprintf(fid1, '%s\n', PhaseDiff);
        
        fclose('all');
    end
end

Answer 1

[Rik]

Use one of the append options from fopen:

'r' Open file for reading.
'w' Open or create new file for writing. Discard existing contents, if any.
'a' Open or create new file for writing. Append data to the end of the file.
'r+' Open file for reading and writing.
'w+' Open or create new file for reading and writing. Discard existing contents, if any.
'a+' Open or create new file for reading and writing. Append data to the end of the file.
'A' Open file for appending without automatic flushing of the current output buffer.
'W' Open file for writing without automatic flushing of the current output buffer.

[Zainab Saka]

This helped me,Thank you!