Simon Brunning wrote: > On Apr 5, 2005 2:04 AM, Raymond Hettinger <[EMAIL PROTECTED]> wrote: >> [Steven Bethard] >> > So do I read this right in preferring >> > [<x> for <y> in <z>] >> > over >> > list(<x> for <y> in <z>) >> >> Yes! > > Why? (Serious question. I'm sure that you have a good reason - I just > can't figure out what it is.) > > The generator expression has the advantage of not leaking references > into the enclosing namespace. What's advantage of the list comp? > The list comprehension is about 15-20% faster according to timeit.py:
C:\Python24\Lib>..\python.exe timeit.py -s "t = range(1000)" "[ x for x in t]" 10000 loops, best of 3: 116 usec per loop C:\Python24\Lib>..\python.exe timeit.py -s "t = range(1000)" "list(x for x in t)" 1000 loops, best of 3: 144 usec per loop C:\Python24\Lib>..\python.exe timeit.py -s "t = range(100000)" "[ x for x in t]" 10 loops, best of 3: 13.9 msec per loop C:\Python24\Lib>..\python.exe timeit.py -s "t = range(100000)" "list(x for x in t)" 10 loops, best of 3: 16.3 msec per loop Alternatively you could just regard the list comprehension as having less clutter on the screen so it may be clearer. -- http://mail.python.org/mailman/listinfo/python-list
