最早见过手写的,类似于下面这种:
import datetime def time_1(): begin = datetime.datetime.Now() sum = 0 for i in xrange(10000000): sum = sum + i end = datetime.datetime.Now() return end-begin print time_1()
输出如下:
➜ Python python time_1.py
0:00:00.280797
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:
import datetime def time_1(): begin = datetime.datetime.Now() sum = 0 for i in xrange(10000000): sum = sum + i end = datetime.datetime.Now() return end-begin if __name__ == '__main__': print time_1() import cProfile 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。
以上就是本文的全部内容,希望对大家学习python程序设计有所帮助。