Several methods for analyzing the python program running time, python program running

Several methods for analyzing the python program running time, python program running

I have seen handwriting at the earliest, similar to the following:

  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()

The output is as follows:

➜  Python python time_1.py0:00:00.280797

 

Another method is to use the timeit module. The method is as follows:

In [5]: import timeitIn [6]: timeit.timeit("sum(range(100))")Out[6]: 1.2272648811340332

You can also use the timeit module on the command line as follows:

➜  Python python -m timeit -s"import time_1 as t" "t.time_1()"0:00:00.28204410 loops, best of 3: 279 msec per loop

Note: The timeit module runs the program multiple times to get a more precise time, so you need to avoid the impact of repeated execution. For example, an operation like x. sort (), because after the first execution, the operation is already sorted, and the accuracy is affected.

 

Another method is to use the cProfile module. The Code is as follows and the name is 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()')

The running result is as follows:

➜  Python python time_1.py0:00:00.282828         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.py0:00:00.284642         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}

The last line in the code at the beginning is cProfile. run ('main () '), prompting that no main () exists. Change main () to the function name.

 

Here is the simplest application. For details, refer to the document or directly help (xxx)