Here are my benchmarks for those interested in version 2.4.3 [EMAIL PROTECTED]:~$ python -V Python 2.4.3 [EMAIL PROTECTED]:~$ python -mtimeit 'for x in range(1000):pass' 10000 loops, best of 3: 64.2 usec per loop [EMAIL PROTECTED]:~$ python -mtimeit 'for x in xrange(1000):pass' 10000 loops, best of 3: 50.5 usec per loop [EMAIL PROTECTED]:~$ python -mtimeit -s'y=range(1000)' 'for x in y:pass' 10000 loops, best of 3: 68.2 usec per loop [EMAIL PROTECTED]:~$ python -mtimeit -s'y=xrange(1000)' 'for x in y:pass' 10000 loops, best of 3: 51.4 usec per loop [EMAIL PROTECTED]:~$ python -mtimeit -s'from itertools import repeat' 'for x in repeat(None, 1000): pass' 10000 loops, best of 3: 45.6 usec per loop [EMAIL PROTECTED]:~$
Alex Martelli wrote: > Tim Roberts <[EMAIL PROTECTED]> wrote: > ... > > xrange used to be better. As I understand it, that's no longer the case. > > measuring is better than guessing: > > brain:~/codejam alex$ python -V > Python 2.5c1 > brain:~/codejam alex$ python -mtimeit 'for x in range(1000):pass' > 10000 loops, best of 3: 71.9 usec per loop > brain:~/codejam alex$ python -mtimeit 'for x in xrange(1000):pass' > 10000 loops, best of 3: 54 usec per loop > brain:~/codejam alex$ python -mtimeit -s'y=range(1000)' 'for x in > y:pass' > 10000 loops, best of 3: 44.8 usec per loop > brain:~/codejam alex$ python -mtimeit -s'y=xrange(1000)' 'for x in > y:pass' > 10000 loops, best of 3: 53.2 usec per loop > brain:~/codejam alex$ > > So: in 2.5 (2.4 too, do your own timings;-) range is better if you can > create the range once and use it repeatedly, xrange if you have to > create the range each time. But actually: > > brain:~/codejam alex$ python -mtimeit -s'from itertools import repeat' > 'for x in repeat(None, 1000): pass' > 10000 loops, best of 3: 41.3 usec per loop > > if you don't actually need the iteration-index in the loop (you just > need to repeat the loop N times), itertools.repeat is even better (well, > if every microsecond counts, anyway;-). > > > Alex -- http://mail.python.org/mailman/listinfo/python-list
