"Steve Holden" <st...@holdenweb.com> wrote in message
news:mailman.462.1292214062.2649.python-l...@python.org...
On 12/12/2010 2:32 PM, Christian Heimes wrote:
Am 12.12.2010 19:31, schrieb Steve Holden:
$ python -m timeit -n20 -- "i = 0" "while 1:" " i+=1" " if i ==
1000000: break"
20 loops, best of 3: 89.7 msec per loop
$ python -m timeit -n20 -- "i = 0" "while True:" " i+=1" " if i ==
1000000: break"
20 loops, best of 3: 117 msec per loop
No argue with that! I was merely making a point that "while 1" executes
different byte code than "while True". Readability is important but
sometimes speed is of the essence. "while 1" is one of the few tricks to
speed up tight loops a bit.
OK, but the figures you quote save you 27.3 ms per million iterations,
for a grand total saving of 27.3 ns per iteration. So "a bit" is hardly
worth considering for most programs, is it?
One these is 30% faster than the other. That's an appreciable difference,
which you can't really just dismiss.
And you can't tell what the overall effect on a program will be: perhaps the
loop will be in a library function , which might be called billions of
times.
--
Bartc
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