How To Turn Newlines In A File To Lines Extending To End Of Line?

I am copying this answer like this for line in fileinput.input(['my_file'], inplace=True): sys.stdout.write('_____ {l}'.format(l=line)) to add four underlines to beginning of

Solution 1:

Strip the whitespace on the line and see if it's non-empty (and thus, truthy). If it's non-empty, do what it did before. Otherwise, it's empty; print the horizontal line. (although I must say 49 characters is somewhat odd)

term_width = 50
with contextlib.closing(fileinput.input(['my_file'], inplace=True)) as f:
    for line in f:
        if line.strip():
            sys.stdout.write('_____ {l}'.format(l=line))
        else:
            sys.stdout.write('\n'.rjust(term_width, '_'))