A use-case for for...else with no break

[Steve D'Aprano]

On Fri, 3 Nov 2017 04:22 pm, Paul Rubin wrote:

> Steve D'Aprano <steve+python at pearwood.info> writes:
>> for x in something():
>>     print(x, end='')
> 
> print(''.join(something()))


I hoped that people would recognise a simplified, toy example used only to
illustrate a technique, rather than an exact copy and paste of something I'm
actually doing.

Try this instead:

for s in sequence:
    if isinstance(s, bytes):
        try:
             s = s.decode.('utf-8')
        except UnicodeDecodeError:
             s = s.decode.('latin-1')
    print(s, end='')
else:
    print()


Without writing a helper function, got a fancy one liner for that too?

Or another example, sometimes you really don't want to wait until the entire
sequence is processed before printing any output.

count = 0
for obj in sequence:
    if count == 60:
        print(' ', time.asctime())
        count = 0
    print('.', end='')
    expensive_time_consuming_process_that_might_take_minutes_or_hours(obj)
    count += 1
else:
    del count
    print()
    print("finished at", time.asctime())


Now honestly, do you think the more complex examples illustrate the point I
was making, and the usefulness of for...else, better than the simple version?

Because I think they make them more complicated and hard to understand, and
distract from the point I am making.



-- 
Steve
“Cheer up,” they said, “things could be worse.” So I cheered up, and sure
enough, things got worse.