MATLAB: How to write in the text file

fprinttext file

hi all, the following code is for writing all of data file names into text file, the problem is the name are not written in the text sequentially

 clear 
 FN1 = 'JDA';
z   = '0',
mn  = 1:12;
yr  = 9:13;
ext = '.ohh';
 for k = 1:numel(yr);
       if yr==9
          tmp = sprintf('%s%s%03d%02d%s',FN1,z,yr(k),mn(k),ext)
          fid = fopen(tmp,'rt'); 
       end
     tmp = sprintf('%s%03d%02d%s',FN1,yr(k),mn(k),ext)
     fid = fopen(tmp,'rt');
    end
          filename = fopen('JDAraw.txt','w');
           fprintf(fid,tmp);

If anyone can correct this for me, I'll appreciate the help.

Best Answer

FN1 = 'JDA';
mn  = 1:12;
yr  = 9:13;
ext = '.ohh';
format = sprintf('%s%%03d%%02d%s\n', FN1, ext);          
data = [yr; mn(1:numel(yr))];                
text = sprintf(format, data(:))
fid = fopen('JDAraw.txt','w');
fprintf(fid, '%s', text)
fclose(fid)

Related Solutions

MATLAB: The error with eval does appear in the code

Using eval for such trivial code like this is a really really bad idea, because you remove all of MATLAB's inbuilt code checking and code hinting tools. Do yourself a favor and learn how to program without eval. Doing so makes your code more faster, more robust and less obfuscated. Read this to know why eval is a really bad programming tool, even though beginners seem to think that it is the greatest tool ever:

http://www.mathworks.com/matlabcentral/answers/196952-how-to-create-new-variables-in-batches-with-strcat

In your case your code probably does not do what you think it does, and this is being exacerbated by using eval. If you look at the value of FN2 it is a very unusual filename:

>> FN2
FN2 = JDA09  10  11  12  13012.ohh

I suspect that you really wanted to do something in a loop like this:

FN1 = 'JDA0';
z   = '0';
mn  = 12;
yr  = 9:13;
ext = '.ohh';
for k = 1:numel(yr)
    tmp = sprintf('%s%02d%d%02d%s',FN1,yr(k),z,mn,ext)
    fid = fopen(tmp,'rt');
    ... other code here
end

Summary Do NOT use eval for such trivial code. And use sprintf to generate the filename from the numbers. Read its documentation to know what formatting options it has.

MATLAB: I am creating a date file using the following script, i want it to print DATES[] in the file the_dates.txt but it’s only printing one date which is 2.0171e+09, that is when i type A(1,1)…i pleading for help

The problem with your file is that you overwrite your Date_num value whenever you calculate a new one. Your DATA variable has no function inside the loop, After the loops, DATA will only replicate Date_num, and is thus superfluous.

Your approach is fine as a Matlab exercise, but for serious work I recommend that you type 'doc datetime' and learn about this and other built-in time and date functions.

Here is version of your code that will work and hopefully do what you want:

Date_num = [];
for iy = 2005:2017
        yr = num2str(iy);
  for im = 1:12
    if im < 10
       mn = sprintf('0%s',num2str(im));
    else
       mn = num2str(im);
    end
    switch im
      case {1 3 5 7 8 10 12}
         M_END = 31;
      case {4 6 9 11}
         M_END = 30;
      otherwise
         %----------------------------------------------------------

         % Check whether this is a leap year or not and then assign
         % the appropriate month end.
         %----------------------------------------------------------
         ny = str2num(yr);
         ly = isequal(floor(ny/4)*4,ny);
         if ly == 1
            M_END = 29;
         else
            M_END = 28;
        end
    end
    for id = 1:M_END
      if id < 10
         dy = sprintf('0%s',num2str(id));
      else
         dy = num2str(id);
      end
      dt = strcat(yr,mn,dy); ndt = str2num(dt);
        for ih = 0:6:18
          if ih < 10
             hr = sprintf('0%s',num2str(ih));
          else
             hr = num2str(ih);
          end
  %         DATES=[];
          Date_STR= strcat(dt,hr);
          Date_num= [Date_num;str2num(Date_STR(end,:))];
        end
      end
    end
  end
  % DATES=vertcat(DATES,[Date_num]);
  fn=sprintf('my_dates.txt');
  fid=fopen(fn,'w');
  fprintf(fid,'%10.2f\n',Date_num);
  fclose(fid);

Best Answer

Related Solutions

MATLAB: The error with eval does appear in the code

MATLAB: I am creating a date file using the following script, i want it to print DATES[] in the file the_dates.txt but it’s only printing one date which is 2.0171e+09, that is when i type A(1,1)…i pleading for help

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