MATLAB: Constructing file identifier from string

#fileidentifierMATLAB

I open several files, write text to the files upon opening them…for example…
fullfileKBDR = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KBDR_',forecastyears(k,:),'.csv')
    fileID1 = fopen(fullfileKBDR, 'w')
    fprintf(fileID1,formatSpec)
      fullfileKMHT = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KMHT_',forecastyears(k,:),'.csv')
      fileID2 = fopen(fullfileKMHT, 'w');
      fprintf(fileID2,formatSpec)
      fullfileKASH = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KASH_',forecastyears(k,:),'.csv')
      fileID3 = fopen(fullfileKASH, 'w');
      fprintf(fileID3,formatSpec)
      fullfileKPWM = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KPWM_',forecastyears(k,:),'.csv')
      fileID4 = fopen(fullfileKPWM, 'w');
      fprintf(fileID4,formatSpec)
But the question is that later in the code, I have a loop where I'm processing data in the loop. I want to be able to construct the file identifier (e.g. fileID1, fileID2, fileID3, fileID4) and write to the file based on the loop counter. So something that would like this, but it doesn't work:
for n = 1:4
            %Do stuff
            nasstr = string(n)
            fileident = strcat('fileID',nasstr)
            fprintf(fileident, 'blah\n')
          end
Can someone share the syntax that would make this work? Thanks.

Best Answer

You can initialize file identifiers as an array, and use them in loop.
fullfileKBDR = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KBDR_','.csv')
fid(1) = fopen(fullfileKBDR, 'w')
fprintf(fileID1,formatSpec)
fullfileKMHT = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KMHT_','.csv')
fid(2) = fopen(fullfileKMHT, 'w');
fprintf(fileID2,formatSpec)
fullfileKASH = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KASH_','.csv')
fid(3) = fopen(fullfileKASH, 'w');
fprintf(fileID3,formatSpec)
fullfileKPWM = strcat('/Users/jkoval/Documents/MATLAB/archived_fod_forecasts/output/KPWM_','.csv')
fid(4) = fopen(fullfileKPWM, 'w');
fprintf(fileID4,formatSpec)
for n = 1:4
    %Do stuff
    nasstr = string(n)
    fid(n)   % this gives file identifier 
end
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