percent faster than format()? (was: Re: optomizations)

[Chris Angelico]

On Wed, Apr 24, 2013 at 12:36 AM, Steven D'Aprano
<steve+comp.lang.python at pearwood.info> wrote:
> # Using Python 3.3.
>
> py> from timeit import Timer
> py> setup = "a = 'spam'; b = 'ham'; c = 'eggs'"
> py> t1 = Timer("'%s, %s and %s for breakfast' % (a, b, c)", setup)
> py> t2 = Timer("'{}, {} and {} for breakfast'.format(a, b, c)", setup)
> py> print(min(t1.repeat()))
> 0.8319804421626031
> py> print(min(t2.repeat()))
> 1.2395259491167963
>
>
> Looks like the format method is about 50% slower.

Figures on my hardware are (naturally) different, with a similar (but
slightly more pronounced) difference:

>>> sys.version
'3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 10:55:48) [MSC v.1600 32 bit (Intel)]'
>>> print(min(t1.repeat()))
1.4841416995735415
>>> print(min(t2.repeat()))
2.5459869899666074
>>> t3 = Timer("a+', '+b+' and '+c+' for breakfast'", setup)
>>> print(min(t3.repeat()))
1.5707538248576327
>>> t4 = Timer("''.join([a, ', ', b, ' and ', c, ' for breakfast'])", setup)
>>> print(min(t4.repeat()))
1.5026834416105999

So on the face of it, format() is slower than everything else by a
good margin... until you note that repeat() is doing one million
iterations, so those figures are effectively in microseconds. Yeah, I
think I can handle a couple of microseconds.

ChrisA