CODEWITHSUNDEEP
matlab
bigTree
bigTree

Reputation: 2183

Writing a text file with fprintf on matlab

I am trying to write a text file using fprintf on matlab. I use a for loop:

fID = fopen('fileName','w');
fSpec = cat(2,repmat('%s', 1, 3),'\n');
for k=1:10
    to_write = [num2str(k) ',' num2str(k*k)];
    fprintf(fID, fSpec, to_write);
end
fclose(fID);

A file is written, but on one line only. I tried opening it with gedit and matlab.

What is wrong?

Upvotes: 3

Views: 5939

Answers (2)

sebastian
sebastian

Reputation: 9696

Your format specifier is somewhat weird. to_write will be a plain string, so why do you construct fSpec to be %s%s%s\n?

If you want one line per loop, you can simply do:

for k=1:10
    to_write = [num2str(k) ',' num2str(k*k)];
    fprintf(fID, '%s\n', to_write);
end

EDIT:

In case %s%s%s\n was designed to match the three strings in [num2str(k) ',' num2str(k*k)]: This is not necessary. The result of [num2str(k) ',' num2str(k*k)] will simply be a single string - so you only need one '%s' format specifier, instead of three.

Upvotes: 4

Fraukje
Fraukje

Reputation: 683

I was able to find two little things in your code.

First, you want to hit return after writing each line, thus \n. Second, you were trying to write a string value using fprint since you were using %s, changing it to %d solved it I think!

So the updated code should read: 

fID = fopen('fileName','w');
fSpec = cat(2,repmat('%d', 1, 3),'\n');
for k=1:10
    to_write = [num2str(k) ',' num2str(k*k)];
    fprintf(fID, fSpec, to_write);
end

fclose(fID);

Upvotes: 0

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