writing maxtrix into a txt file

I am trying to write a maxtrix into a txt file which contains other information, so i am wondering how i would go about this? could i use dlmwrite, will this write everything in the same file as my other information? Thanks.

p.s. right now i am writing every number in one by one with a nested loop, takes a long time to do since i have a 24000X103 matrix, and also takes forever to open.

Answer 1

[Walter Roberson]

dlmwrite() cannot handle a mix of text and numbers. It can handle numbers alone, and it can handle text alone (when backed in to a corner.)

Are you just trying to append a matrix to an existing file? If so then:

thisfmt = [repmat('%g ', 1, size(YourMatrix,2)-1),, '%g\n'];
fid = fopen('YourExistingFile.txt', 'at');
printf(fid, thisfmt, YourMatrix .');  %transpose is critical!  
fclose(fid)

Adjust the %g to whatever is appropriate.

[Andy]

thanks, that worked, just one more question, is there a limit as to how far to the right the txt file can be written? i mean when matlab writes the matrix in, it stopped before it wrote all 24000 numbers in and went to the next line and then continued there

[Walter Roberson]

The above code will write 24000 rows each containing 103 columns -- "row major order".

Did you want to write by columns across rather than by rows?

thisfmt = [repmat('%g ', 1, size(YourMatrix,1)-1),, '%g\n'];

fid = fopen('YourExistingFile.txt', 'at');

printf(fid, thisfmt, YourMatrix); %NO transpose!

fclose(fid)