On 3/17/2010 1:35 AM, Patrick Maupin wrote:
def a(s, count, lenfunc):
... for i in xrange(count):
... z = lenfunc(s)
...
>>> a('abcdef', 100000000, len)
>>> a('abcdef', 100000000, str.__len__)
Running cPython 2.6 on my machine, len() runs about 3 times faster
than str.__len__(). The overhead of checking that an object is usable
with a particular class method far outweighs the cost of creating the
bound method!
Wow, this so surprised me, that I had to try it with 3.1 (on winxp), and
got a similar result (about 2.6x longer with str.__len__). This is a
real lesson in measure, don't guess, and how premature 'optimization'
may be a pessimization. Thanks.
Terry Jan Reedy
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