Is it right this way?

I have a intpts variable:

intpts

intpts =

   30.0000   20.0000
   28.7500   17.5000
   28.0000   16.0000
   27.5000   15.0000
   31.0000   22.0000
   32.5000   17.5000
   30.0000   15.0000
   28.7500   13.7500
   35.0000   20.0000
   36.2500   21.2500
   32.5000   13.7500

I would like to create a .txt file that contains the previous number. Is it right to do this?

 nomefile = fopen ( 'file.txt' , 'wt');
 fprintf ( nomefile , '%6.2g %8.4g\n' , intpts);
 fclose (nomefile);

Is there another way to do this in a simple or more effective metod? What do you suggest?

Answer 1

[Walter Roberson]

fprintf ( nomefile , '%6.2g %8.4g\n' , intpts.');

You could also use csvwrite() or dlmwrite().

In time you may find yourself migrating back to the fopen/fprintf/fclose version, due to the extra control it gives you about choosing formats column by column, and for putting in headers and for writing multiple variables.

[Francesco]

You have put .' and dpb has put only '. Can I know the difference between this two situation?

[Walter Roberson]

http://www.mathworks.com/help/matlab/ref/transpose.html

http://www.mathworks.com/help/matlab/ref/ctranspose.html

Answer 2

[dpb]

Other than you need a transpose operator (') on the array to write in row-major order --

fprintf(nomefile ,'%6.2g %8.4g\n',intpts');

That's not terribly onerous is it?

The alternative could be dlmwrite which lets you use the file name instead of file handle which is kinda convenient but it doesn't allow more than one format for the full output so your case of wanting different format by column can't be handled.

dlmwrite('file.txt',intpts,'delimiter',' ','precision','%.4f')

It also handles the transpose transparently being a higher-level abstraction of fprintf

But, outside that, if you want a specific output format, you specify it, yes...

[Francesco]

dlmwrite('filedlm.txt',intpts,' ',' ','%10.5f','%.4f')

With this command Matlab said:

??? Error using ==> dlmwrite at 114
  is not a valid attribute or row offset.

As delimiter I can't use the tab character?

[Francesco]

dlmwrite('file.txt',intpts,'delimiter',' ','precision','%.4f')

Sorry this is the correct line command as you said!

[Walter Roberson]

The first five inputs are expected to be filename,M,delimiter,row,col so it appears that you are attempting to pass ' ' for the row parameter and '%10.5f' as the column parameter. Those must be numeric when they are supplied.

In dpb's answer the word 'delimiter' is a keyword, and 'precision' is a keyword.

dlmwrite() only allows you to pass one 'precision' string. If you need different formats for different columns then don't use dlmwrite()

[Francesco]

But in the txt file there is no two columns as I prefer but a one big row? What's the matter?

[Walter Roberson]

What have you corrected the dlmwrite() call to now be?

[Walter Roberson]

I'm going to bed now. If you want to keep fighting your code so you can take advantage of the "simplicity" of dlmwrite() instead of the "complexity" of fopen() fprintf() fclose(), then feel free to do so.