Getting some element from sets.Set

[Raymond Hettinger]

>      $ python -m timeit -s "s = set('abcdef')" "x = iter(s).next()"
>      1000000 loops, best of 3: 0.399 usec per loop
>
>      $ python -m timeit -s "s = set('abcdef')" "x = s.pop(); s.add(x)"
>      1000000 loops, best of 3: 0.339 usec per loop
>
> So it looks like it's more efficient to use s.pop() + s.add().


There's a faster, cleaner way:

>python -m timeit -s "s = set('abcdef')" "x = iter(s).next()"
1000000 loops, best of 3: 0.539 usec per loop

>python -m timeit -s "s = set('abcdef')" "x = s.pop(); s.add(x)"
1000000 loops, best of 3: 0.465 usec per loop

>python -m timeit -s "s = set('abcdef')" "for x in s: break"
1000000 loops, best of 3: 0.175 usec per loop


FWIW, the latter approach is general purpose and works with any
iterable (useful for reading the first line of file objects for
example).


Raymond