Add a large number of comma separated numbers to a txt file

I have a .txt file that has two columns. It looks like this

Age                    3
Salary                 52661
Average working hours  40
Conditions             1, 26, 65, 89, 20, 2, 2

I would like to add a row

Favorite numbers       2, 8, 66

Birdman has given an answer to this question in another topic.

fid=fopen('data.txt','a+');
fprintf(fid,'\n%s       %d, %d, %d\n',"Favorite numbers",2,8,66);
fclose(fid)

Unfortnuately I forgot to add that the amount of doubles (in my case "favorite number"s) can be humongous (hundreds of numbers).

Is there a way to get the %d multiple times in the code without typing it out hundred of times.

I tried

a='%d, ';
rep=repmat(a,1,k) %k being the number of favorite numbers
fprintf([fid,'\n%s            ' rep ' \n','Favorite numbers', vector_with_numbers]);

this doesn't work, just prints rep. Any ideas?

Answer 1

[Fangjun Jiang]

%d can be used repeatedly automatically, run this to see the effect:

fprintf(1,'\n%s         ',"favorite numbers");
fprintf(1,',%d',1:20);
fprintf(1,'\n');

[lou]

Thank you. However, there added line should also contain a string ("Favorite numbers") a space between the string and the numbers. Any idea how to do that?

Favorite numbers          1,2,3,4,5,6,7,8,9,11,12

[Fangjun Jiang]

See the update. Add spaces in

'\n%s   '

as you want.

[lou]

Awesome, thank you!