最早见过手写的,类似于下面这种:
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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
另外一种方法是使用timeit模块,使用方法如下:
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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:
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➜ 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:
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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:
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➜ 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。