How do I create a text file in a loop?

I am sure this has been asked before, but searching for it has lead me nowhere.

I need to create a text file and then have the code create copies of that file after changing a few things.

This is what I need the file to look like:

This is my code so far, but I can't seem to get the file to even open. I haven't attempted the loop part. I have placed the "CONTROL.txt" file in the MATLAB directory, but still nothing.

Any help would be appreciated.

fopen('CONTROL.txt','r');

    fprintf('12 12 30 18  \n'); % This is the date line
    fprintf('3 \n'); % This is the number of starting locations
    fprint('-71.166889 111.366531  10.0 \n')% This is a list of starting locations, including elevation (agl)
    fprint('-71.166889 111.366531  2500.0 \n') %This is the second starting location.
    fprint('-71.166889 111.366531  5000.0 \n') % This is a third starting location
    fprintf('-240 \n') % Number of hours for back trajectory. Needs to have a negative sign
    fprint('0 \n')% Not sure what this is, just leave it as 0
    fprint('30000.0 \n')    % Height of model, leave at 30000.0
    fprint('5 \n')% Number of meterological data files, possibly.
    fprint('C:/hysplit4/MetData/gdas1.dec10.w5 \n') % The first metdata file.
    fprint('C:/hysplit4/MetData/gdas1.dec10.w1 \n') % The second net data file... and so on
    fprint('C:/hysplit4/MetData/gdas1.dec10.w2 \n')
    fprint('C:/hysplit4/MetData/gdas1.dec10.w3 \n')
    fprint('C:/hysplit4/MetData/gdas1.dec10.w4 \n')
    fprintf('./tdump10123018  \n')% Possibly the name of the tdump files
    fclose(fid);

Answer 1

[KSSV]

You need not to write line by line....make your entire content to a cell array and write this cell into text file, in a single step. Check the below example code:

A = {'10 12 30 18' ; '3' ; '-71.166889 111.366531 10.0' ; '-240' ; '0' ; 
    'C:/hysploit4/MetData/gdas1.dec10.w5'} ; ;

% Write to file 
fid = fopen('data.txt','wt') ;
fprintf(fid,'%s\n',A{:});
fclose(fid) ;

[C G]

Awesome! Thanks. Now, how do I create the loop part? For example, The next file would change the first variable to '11 01 30 18'.

[KSSV]

How and why your generating this data?

[C G]

Ultimately, I need to create a data file for a program that I am trying to automate. Currently, running the program through its user GUI requires 45 min per run and I have 408 runs to do, not including the inevitable times I will mess up the run.

Step 1: Create a loop in Matlab to write the control files... all 408 or 1600+ depending on the loop and how the first date is parsed.

Step 2: Run the program calling up each CONTROL file. Create the required text files needed for my analysis.

Step 3. Celebrate.

Answer 2

[C G]

Just in case there are any inquiring minds out there. This code is not the best, but it works. I am reading in an excel spreadsheet with varying ranges. I then create a loop that writes a text file with variable A and then a bunch of stuff, calling it file1.txt before moving on to the next variable. In this case, the first line is changed to variable B and it is called file2.txt.

 A = xlsread(filename,sheet,xlRange1);   %Or alternatively A= [1,2,3,4,5,6]
B = xlsread(filename,sheet,xlRange2);
C = xlsread(filename,sheet,xlRange3);
D = xlsread(filename,sheet,xlRange4);

 F = {A,B,C,D};
for k = 1:numel(F)
  [fid,msg] = fopen(sprintf('file%d.txt',k),'wt');
  assert(fid>=3,msg)
  fprintf(fid,'%2.0f %2.0f %2.0f %2.0f %2.0f %2.0f',F{k}(1:6));
  P={'';'3';'-71.166889 111.366531  10.0';'-71.166889 111.366531  2500.0';'-71.166889 111.366531 
 5000.0';'-240';'0';'30000.0';'5';'C:/hysplit4/MetData/gdas1.dec10.w5';
 'C:/hysplit4/MetData/gdas1.dec10.w1';'C:/hysplit4/MetData/gdas1.dec10.w2';'C:/hysplit4/MetData/gdas1.dec10.w3';'C:/hysplit4/MetData/gdas1.dec10.w4';
 './tdump10123018';} ; 
 fprintf(fid,'%s\n',P{:});
 fclose(fid);
 end