python timeit study notes

Introduction

• timeit is a package that comes with python to test the execution time of the code.

How to use

import timeit

Related methods

• timeit(stmt='pass', setup='pass', timer=<defaulttimer>, number=1000000)
  Return:
  Return the time used to execute the stmt code number times, in seconds, float type

     stmt：要执行的那段代码

     setup：执行代码的准备工作，不计入时间，一般是import之类的

     timer：这个在win32下是time.clock()，linux下是time.time()，默认的，不用管

     number：要执行stmt多少遍

Timer class

The functions in the Timer class are the same as the two functions described above

class timeit.Timer(stmt='pass', setup='pass',timer=<timer function>)
    Timer.timeit(number=1000000)
    Timer.repeat(repeat=3,number=1000000)

就相当于
timeit(stmt='pass', setup='pass', timer=<defaulttimer>, number=1000000)
= Timer(stmt='pass', setup='pass', timer=<timerfunction>).timeit(number=1000000)
repeat(stmt='pass', setup='pass', timer=<defaulttimer>, repeat=3, number=1000000)
= Timer(stmt='pass', setup='pass', timer=<timerfunction>).repeat(repeat=3, number=1000000)

Let's look at a simple example

import timeit
import math
import pprint

def myfun():
    for i in range(100):
        for j in range(2, 10):
            math.pow(i, 1/j)

n = 100

t1 = timeit.timeit(stmt=myfun, number=n)
pprint.pprint(t1)
t2 = timeit.repeat(stmt=myfun, number=n, repeat=5)
pprint.pprint(t2)

print()

timeitObj = timeit.Timer(stmt=myfun)
t3 = timeitObj.timeit(number=n)
pprint.pprint(t3)
t4 = timeitObj.repeat(number=n, repeat=5)
pprint.pprint(t4)