python timeit 模块

[root@cdn ~]# python -m timeit '"_".join(str(n) for n in range(100))'
10000 loops, best of 3: 37.5 usec per loop
[root@cdn ~]# python -m timeit '"_".join([str(n) for n in range(100)])'
10000 loops, best of 3: 32.6 usec per loop
[root@cdn ~]# python -m timeit '"_".join(map(str,range(100)))'
10000 loops, best of 3: 22.2 usec per loop
[root@cdn ~]# python -m timeit '"_".join([str(n) for n in xrange(100)])'
10000 loops, best of 3: 31.8 usec per loop

python -m timeit [-n N] [-r N] [-s S] [-t] [-c] [-h] [statement ...]
Where the following options are understood:

-n N, --number=N
how many times to execute ‘statement’

-r N, --repeat=N
how many times to repeat the timer (default 3)

-s S, --setup=S
statement to be executed once initially (default pass)

-t, --time
use time.time() (default on all platforms but Windows)

-c, --clock
use time.clock() (default on Windows)

-v, --verbose
print raw timing results; repeat for more digits precision

-h, --help
print a short usage message and exit

[root@cdn ~]# python
Python 2.6.6 (r266:84292, Jan 21 2013, 17:47:21)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-51)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import timeit
>>> timeit.timeit('char in text' ,setup='text= "sample string";char = "g"')
0.10500788688659668
>>> timeit.timeit('text.find(char)' ,setup='text= "sample string";char = "g"')
0.24353289604187012
>>> text= "sample string";char = "g"
>>> text.find(char)
12

>>> t=timeit.Timer('char in text', setup=' text=" sample string"; char = "g"')
Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python2.6/timeit.py", line 136, in __init__
code = compile(src, dummy_src_name, "exec")
File "", line 4
_t0 = _timer()
^
IndentationError: unindent does not match any outer indentation level
###注意 setup里的字符串不能有空格
>>> t=timeit.Timer('char in text', setup='text=" sample string"; char = "g"')
>>> t.timeit()
0.10593914985656738
>>> t.repeat()
[0.10739803314208984, 0.10854411125183105, 0.10851407051086426]
>>>

python中使用try/exception

[root@cdn ~]# python -m timeit 'try:' '  str.__nonzero__' 'except AttributeError:' '  pass'
1000000 loops, best of 3: 1.71 usec per loop
[root@cdn ~]# python -m timeit 'if hasattr(str, "__nonzero__"): pass'
1000000 loops, best of 3: 0.836 usec per loop
[root@cdn ~]# python -m timeit 'try:' '  int.__nonzero__' 'except AttributeError:' '  pass'
10000000 loops, best of 3: 0.112 usec per loop
[root@cdn ~]# python -m timeit 'if hasattr(int, "__nonzero__"): pass'
1000000 loops, best of 3: 0.209 usec per loop

timeit访问自定义函数，使用setup参数。

def test():
    L=[]
    for i in range(100):
        L.append(i)

if __name__ == '__main__':
    import timeit
    print(timeit.timeit("test()",setup="from __main__ import test"))