Performance of int/long in Python 3

[Lele Gaifax]

jmfauth <wxjmfauth at gmail.com> writes:

> Now replace i by a char, a representent of each "subset"
> of the FSR, select a method where this FST behave badly
> and take a look of what happen.

You insist in cherry-picking a single "method where this FST behave
badly", even when it is so obviously a corner case (IMHO it is not
reasonably a common case when you have relatively big chunks of ASCII
characters where you are adding one single non-ASCII char...)

Anyway, these are my results on the opposite case, where you have a big
chunk of non-ASCII characters and a single ASCII char added:

Python 2.7.3 (default, Jan  2 2013, 13:56:14) 
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import timeit
>>> timeit.repeat("'€' * 1000 + 'z'")
[0.2817099094390869, 0.2811391353607178, 0.2811310291290283]
>>> timeit.repeat("u'œ' * 1000 + u'\U00010001'")
[0.549591064453125, 0.5502040386199951, 0.5490291118621826]
>>> timeit.repeat("u'\U00010001' * 1000 + u'œ'")
[0.3823568820953369, 0.3823089599609375, 0.3820679187774658]
>>> timeit.repeat("u'\U00010002' * 1000 + 'a'")
[0.45046305656433105, 0.45000195503234863, 0.44980502128601074]

Python 3.3.0 (default, Mar 18 2013, 12:00:52) 
[GCC 4.7.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import timeit
>>> timeit.repeat("'€' * 1000 + 'z'")
[0.23264244200254325, 0.23299441300332546, 0.2325888039995334]
>>> timeit.repeat("'œ' * 1000 + '\U00010001'")
[0.3760241370036965, 0.37552819900156464, 0.3755163860041648]
>>> timeit.repeat("'\U00010001' * 1000 + 'œ'")
[0.28259182300098473, 0.2825558360054856, 0.2824251129932236]
>>> timeit.repeat("'\U00010002' * 1000 + 'a'")
[0.28227063300437294, 0.2815949220021139, 0.2829978369991295]

IIUC, while it may be true that Py3 is slightly slower than Py2 when the
string operation involves an internal representation change (all your
examples, and the second operation above), in the much more common case
it is considerably faster. This, and the fact that Py3 actually handles
the whole Unicode space without glitches, make it a better environment
in my eyes. Kudos to the core team!

Just my 0.45-0.28 cents,
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 at metapensiero.it  |                 -- Fortunato Depero, 1929.