On Sun, 12 Dec 2010 23:20:40 -0500, Steve Holden wrote: > On 12/12/2010 2:32 PM, Christian Heimes wrote: [...] >> 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?
I don't think anyone is saying that people should routinely use "while 1" for loops because they're faster than the alternatives. But it is a real, if small, optimization for a particular class of tight loops. Using the figures shown by Christian, it could be a 20-25% speed up on extremely tight loops. You're right though, it's hardly worth the effort for large, expensive loops though -- but then on the other hand, "while 1" is not so unreadable that it should be avoided. I'm actually quite fond of the look of "while 1:", and sometimes use it, not because it's faster, but just because I like it. -- Steven -- http://mail.python.org/mailman/listinfo/python-list