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From: Lele Gaifax <lele@metapensiero.it>
Subject: Re: percent faster than format()?
Date: Tue, 23 Apr 2013 17:44:15 +0200
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Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> writes:

> So again, why is one faster than the other? What am I missing?

The .format() syntax is actually a function, and that alone carries some
overload. Even optimizing the lookup may give a little advantage:

>>> from timeit import Timer
>>> setup = "a = 'spam'; b = 'ham'; c = 'eggs'"
>>> t1 = Timer("'%s, %s and %s for breakfast' % (a, b, c)", setup)
>>> t2 = Timer("'{}, {} and {} for breakfast'.format(a, b, c)", setup)
>>> print(min(t1.repeat()))
>>> print(min(t2.repeat()))
>>> setup = "a = 'spam'; b = 'ham'; c = 'eggs'; f = '{}, {} and {} for breakfast'.format"
>>> t3 = Timer("f(a, b, c)", setup)
>>> print(min(t3.repeat()))
0.3076407820044551
0.44008257299719844
0.418146252995939

But building the call frame still takes its bit of time.

ciao, lele.
-- 
nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri
real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia.
lele@metapensiero.it  |                 -- Fortunato Depero, 1929.