MATLAB Answers


Writing a text file with information from a data file

Asked by Jonathan
on 25 Jun 2012

Hi, I need to be able to take a .dat file that contains 5 strings of the filenames of .jpg images, and out put a .txt file that contains the name of each string and other data for EACH string (i.e. each .jpg image). I figured out how to generate this for one of the strings, but I don't know how to do it for all of the strings. Maybe use some sort of loop?

 fileID = fopen('nameOfFile.dat');
 filename = fgets(fileID)
 fileID2 = fopen('nameOfFile.txt','wt');
 info = 'blah blah';
 num = 5;
 fprintf(fileID2,'Filename: %s\n Info: %s\n Number:  %g\n',filename,info,num);


UPDATE: I have figured out how to generate this for all of the strings, but I can only do it if I know how many strings there are. I need to be able to do it with any input data file (not just one with 5 strings). Also, I need the info and num to be able to be different for each filename.

fileID = fopen('nameOfFile.txt','wt');
filename = textread('nameOfFile.dat','%s\n')  
info = 'blah blah blah';
num = 5;
fprintf(fileID,'Filename: %s\nInfo: %s\nNumber: %g\n',filename{1},info,num,filename{2},info,num,filename{3},info,num,filename{4},info,num,filename{5},info,num);

  1 Comment

I figured it out! It was much simpler than I thought.

fileID = fopen('nameOfFile.txt','wt');

filename = textread('nameOfFile.dat','%s\n');
for i = 1:length(filename)
info = 'blah blah blah';
num(i) = 5;
fprintf(fileID,'Filename: %s\nInfo: %s\nNumber: %g\n\n',filename{i},info,num(i));


1 Answer

Answer by per isakson
on 25 Jun 2012
 Accepted answer

This is a hint!

 % or a more specific wildcard pattern
 sad = dir( fullfile( folder_spec, '*.dat' ) );  
 file_name_list = permute( { }, [2,1] );  %  row vector
 fileID = fopen('nameOfFile.txt','wt');
 for file_name = file_name_list   % loop over all files
      image_file_name = textread( fullfile(folder_spec,file_name{:}, ... );
      info = something
      num = something else
      fprintf( fileID, 'Filename: %s\nInfo: %s\nNumber: %g\n'  ...
                       , image_file_name, info, num )
  fclose( fileID );


Sorry, but this doesn't help me very much. I'm still confused.

Cannot help without better description of the problem

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