Rafe <[EMAIL PROTECTED]> wrote: > On Dec 1, 7:26?am, "Filip Gruszczy?ski" <[EMAIL PROTECTED]> wrote: > > I have following question: if I use > > > > from module import * > > > > instead > > > > from module import Class > > > > am I affecting performance of my program? I believe, that all those > > names must be stored somewhere, when they are imported and then > > browsed when one of them is called. So am I putting a lot of "garbage" > > to this storage and make those searches longer? > > Why use it if you don't need it? Your post implies a choice and the > '*' import can really make things muddy if it isn't actually necessary > (rare). Why not just import the module and use what you need? It is > way easier to read/debug and maintains the name-space.
Importing the module is actualy slower... If you import the name into your namespace then there is only one lookup to do. If you import the module there are two. $ python -m timeit -s 'from timeit import Timer' 'Timer' 10000000 loops, best of 3: 0.0784 usec per loop $ python -m timeit -s 'import timeit' 'timeit.Timer' 1000000 loops, best of 3: 0.243 usec per loop I'm not suggestion you should ever use "from module import *" only ever import the things you actually need, eg "from module import MyClass, my_function" And here is the test again, actually calling something with the same difference in execution speed :- $ python -m timeit -s 'from os import nice' 'nice(0)' 1000000 loops, best of 3: 1.21 usec per loop $ python -m timeit -s 'import os' 'os.nice(0)' 1000000 loops, best of 3: 1.48 usec per loop -- Nick Craig-Wood <[EMAIL PROTECTED]> -- http://www.craig-wood.com/nick -- http://mail.python.org/mailman/listinfo/python-list
