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()
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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
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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
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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()' )
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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}
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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。