access list diff

gistfile1.py

# Cfr. http://rickystewart.wordpress.com/2013/09/03/why-sorting-an-array-makes-a-python-loop-faster/

from __future__ import print_function
import random
import timeit

MAX = int(1e6)
ls = [x for x in range(MAX)]
lu = [x for x in range(MAX)]
random.shuffle(lu)

def foo(seq):
    sum = 0
    for i in seq:
        sum += i
    return sum

def bar(seq):
    for i in seq:
        pass

if __name__ == '__main__':
    setup = 'from __main__ import ls, lu, foo, bar'
    rep = 500
    for f in ('foo', 'bar'):
        for t, lst in (('slow', 'lu'), ('fast', 'ls')):
            print("({}) {}: {:.5f}".format(
                f, t, timeit.timeit('%s(%s)' % (f,lst), setup, number=rep)/rep))

"""
crap0101@orange:/tmp$ python t.py # Python 2.7.3
(foo) slow: 0.16535
(foo) fast: 0.06115
(bar) slow: 0.10698
(bar) fast: 0.02427
crap0101@orange:/tmp$ python3 t.py # Python 3.2.3
(foo) slow: 0.19056
(foo) fast: 0.07546
(bar) slow: 0.10368
(bar) fast: 0.02167
crap0101@orange:/tmp$ ~/compilati/pypy3-2.1-beta1-linux64/bin/pypy t.py
(foo) slow: 0.34856
(foo) fast: 0.05094
(bar) slow: 0.00303
(bar) fast: 0.00302
crap0101@orange:/tmp$ ~/compilati/jython2.7b1/jython t.py
(foo) slow: 0.21446
(foo) fast: 0.11107
(bar) slow: 0.14249
(bar) fast: 0.05194

"""