Using timeit

https://docs.python.org/3/library/timeit.html

INTRODUCTION

This module provides a simple way to time small bits of Python code. It has both a Command-Line Interface as well as a callable one.

import timeit

# class timeit.Timer(stmt='pass', setup='pass', timer=<timer function>, globals=None)

t1 = timeit.Timer(stmt="t=a ; a=b ; b=t", setup="a=1 ; b=2")
t2 = timeit.Timer(stmt="(a,b) = (b,a)", setup="a=1 ; b=2")
print(t1.timeit(number=10))   # number=1000000 is the default
print(t2.repeat(repeat=3, number=10))   # return a list with 3 results
print(min(t2.repeat(10)))   # this is what we typically want

import random
import timeit

def mysort(L):
    L[:] = sorted(L)

alist = list(range(pow(10,6)))
random.shuffle(alist)

t1 = timeit.Timer(stmt="mysort(alist)", 
    setup="from __main__ import mysort, alist")   # using strings

#t1 = timeit.Timer(lambda: mysort(alist))   # using a callable

print(t1.timeit(1))   # single run

# Three functions are available.
#
# timeit.timeit(stmt='pass', setup='pass', timer=<default timer>,
#     number=1000000, globals=None)
#
# timeit.repeat(stmt='pass', setup='pass', timer=<default timer>,
#     repeat=5, number=1000000, globals=None)
#
# timeit.default_timer()
#     The default timer, which is always time.perf_counter() [Py3.3+].

print(timeit.timeit("sum(range(pow(10,6)))", number=1))
print(timeit.timeit(lambda: sum(range(pow(10,6))), number=1))

print(timeit.repeat("sum(range(pow(10,6)))", repeat=3, number=1))
print(timeit.repeat(lambda: sum(range(pow(10,6))), repeat=3, number=1))