Write data from for loop into a file

I want to write a file that displays the following output:

period 1 step 1

save

period 1 step 2

save

period 2 step 1

save

The for loop creates the correct output I want but creates an empty .txt file.

for i=1:951
    for j=1:2
   s=fprintf('period %d step %d \n\tsave\n',i,j);
    end
end
fileID = fopen('SA_SP951.txt','w');
fprintf(fileID,s);
fclose(fileID);

Answer 1

[Stephen23]

You need to open the file before the loop, print the text inside the loop, and close the file after the loop:

[fid,msg] = fopen('SA_SP951.txt','wt');
assert(fid>=3,msg)
for ii = 1:951
    for jj = 1:2
        fprintf(fid, 'period %d step %d \n\tsave\n', ii, jj)
    end
end
fclose(fid);

Or alternatively you could collect the character vectors that you generate inside loop into one array (e.g. a cell array) (which seems to be what you were trying to do), but this would be more complex, less efficient, and has no obvious benefit for your requirements.