Python-сообщество

def foo(x):
    return x % 2
def bar(x):
    return x > 10
def func1():
     lst = [foo(x) for x in xrange(10000000) if bar(x)]
def func2():
     lst = filter(bar, map(foo, xrange(10000000)))
t1 = timeit.Timer(func1, 'from __main__ import func1, foo')
t2 = timeit.Timer(func2, 'from __main__ import func2, foo')
print t1.timeit(1)
print t2.timeit(1)

2.43812799454
2.16352391243

# -*- coding:utf-8 -*-
import timeit
....
def func1():
     lst = [x % 2 for x in xrange(10000000) if x > 10]
def func2():
     lst = filter(bar, map(foo, xrange(10000000)))
....

0.842472791672
2.13915705681

def func1():
     lst = [x % 2 for x in xrange(10000000) if x > 10]
def func2():
     lst = filter(lambda x: x > 10, map(lambda x: x % 2, xrange(10000000)))

0.844331979752
2.1546831131

user_uid = '10002'
user_name = next(x.split(':')[0] for x in open('passwd.txt') if x.split(':')[2] == user_uid)
print(user_name)

>>> import itertools
>>> it = itertools.count()
>>> next(it)
0
>>> next(it)
1
>>> next(it)
2
>>>

import timeit
from itertools import ifilter, imap
def foo(x):
    return x % 2
def bar(x):
    return x > 0
    
def func1():
     sum( [foo(x) for x in xrange(100000) if bar(x)] )
     
def func2():
     sum( ifilter(bar, imap(foo, xrange(100000))) )
     
t1 = timeit.Timer(func1, 'from __main__ import func1, foo')
t2 = timeit.Timer(func2, 'from __main__ import func2, foo')
print t1.repeat(3, 10)
print t2.repeat(3, 10)

[0.6189520359039307, 0.6175930500030518, 0.620582103729248]
[0.568681001663208, 0.5698568820953369, 0.5771739482879639]

def func1():
     sum( [x % 2 for x in xrange(100000) if x > 0] )
    
def func2():
     sum( ifilter(lambda x: x > 0, imap(lambda x: x % 2, xrange(100000))) )
     

[0.20290303230285645, 0.2011399269104004, 0.19998598098754883]
[0.5880811214447021, 0.5824930667877197, 0.5833539962768555]

[x for x ]

(x for x)