最早见过手写的，类似于下面这种：

  1 import datetime
  2 
  3 def time_1():
  4     begin = datetime.datetime.now()
  5     sum = 0
  6     for i in xrange(10000000):
  7         sum = sum + i
  8     end = datetime.datetime.now()
  9     return end-begin
 10 
 11 print time_1()

输出如下：

?  Python python time_1.py
0:00:00.280797

 

另外一种方法是使用timeit模块，使用方法如下：

In [5]: import timeit

In [6]: timeit.timeit("sum(range(100))")
Out[6]: 1.2272648811340332

还可以在命令行上使用这种timeit模块，如下：

?  Python python -m timeit -s"import time_1 as t" "t.time_1()"
0:00:00.282044

10 loops, best of 3: 279 msec per loop

注意：timeit模块会多次运行程序以获得更精确的时间，所以需要避免重复执行带来的影响。比方说x.sort()这种操作，因为第一次执行之后，后边已经是排好的了，准确性就收到了影响。

 

还有一种方法是使用cProfile模块，代码如下，名字为time_1.py:

  1 import datetime
  2 
  3 def time_1():
  4     begin = datetime.datetime.now()
  5     sum = 0
  6     for i in xrange(10000000):
  7         sum = sum + i
  8     end = datetime.datetime.now()
  9     return end-begin
 10 
 11 if __name__ == '__main__':
 12     print time_1()
 13 
 14 import cProfile
 15 cProfile.run('time_1()')

运行程序结果如下：　　

?  Python python time_1.py
0:00:00.282828
         2 function calls in 0.000 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    0.000    0.000 <string>:1(<module>)
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}


Traceback (most recent call last):
  File "time_1.py", line 15, in <module>
    cProfile.run('main()')
  File "/usr/lib/python2.7/cProfile.py", line 29, in run
    prof = prof.run(statement)
  File "/usr/lib/python2.7/cProfile.py", line 135, in run
    return self.runctx(cmd, dict, dict)
  File "/usr/lib/python2.7/cProfile.py", line 140, in runctx
    exec cmd in globals, locals
  File "<string>", line 1, in <module>
NameError: name 'main' is not defined
?  Python vi time_1.py 
?  Python python time_1.py
0:00:00.284642
         5 function calls in 0.281 seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    0.281    0.281 <string>:1(<module>)
        1    0.281    0.281    0.281    0.281 time_1.py:3(time_1)
        2    0.000    0.000    0.000    0.000 {built-in method now}
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

一开始代码里最后一行写的是cProfile.run('main()')，提示没有main（），将main（）改成函数名字就可以了

 

这里是最简单的应用，具体大家可以去看看文档，或者直接help(xxx)