How to use timeit module

Question

I understand the concept of what timeit does but I am not sure how to implement it in my code.

How can I compare two functions, say insertion_sort

Answer 1

lets setup the same dictionary in each of the following and test the execution time.

The setup argument is basically setting up the dictionary

Number is to run the code 1000000 times. Not the setup but the stmt

When you run this you can see that index is way faster than get. You can run it multiple times to see.

The code basically tries to get the value of c in the dictionary.

import timeit

print('Getting value of C by index:', timeit.timeit(stmt="mydict['c']", setup="mydict={'a':5, 'b':6, 'c':7}", number=1000000))
print('Getting value of C by get:', timeit.timeit(stmt="mydict.get('c')", setup="mydict={'a':5, 'b':6, 'c':7}", number=1000000))

Here are my results, yours will differ.

by index: 0.20900007452246427

by get: 0.54841166886888

Answer 2

Example of how to use Python REPL interpreter with function that accepts parameters.

>>> import timeit                                                                                         

>>> def naive_func(x):                                                                                    
...     a = 0                                                                                             
...     for i in range(a):                                                                                
...         a += i                                                                                        
...     return a                                                                                          

>>> def wrapper(func, *args, **kwargs):                                                                   
...     def wrapper():                                                                                    
...         return func(*args, **kwargs)                                                                  
...     return wrapper                                                                                    

>>> wrapped = wrapper(naive_func, 1_000)                                                                  

>>> timeit.timeit(wrapped, number=1_000_000)                                                              
0.4458435332577161                                                                                        

Answer 3

If you want to compare two blocks of code / functions quickly you could do:

import timeit

start_time = timeit.default_timer()
func1()
print(timeit.default_timer() - start_time)

start_time = timeit.default_timer()
func2()
print(timeit.default_timer() - start_time)

Answer 4

for me, this is the fastest way:

import timeit
def foo():
    print("here is my code to time...")


timeit.timeit(stmt=foo, number=1234567)

Answer 5

The built-in timeit module works best from the IPython command line.

To time functions from within a module:

from timeit import default_timer as timer
import sys

def timefunc(func, *args, **kwargs):
    """Time a function. 

    args:
        iterations=3

    Usage example:
        timeit(myfunc, 1, b=2)
    """
    try:
        iterations = kwargs.pop('iterations')
    except KeyError:
        iterations = 3
    elapsed = sys.maxsize
    for _ in range(iterations):
        start = timer()
        result = func(*args, **kwargs)
        elapsed = min(timer() - start, elapsed)
    print(('Best of {} {}(): {:.9f}'.format(iterations, func.__name__, elapsed)))
    return result

Answer 6

simply pass your entire code as an argument of timeit:

import timeit

print(timeit.timeit(

"""   
limit = 10000
prime_list = [i for i in range(2, limit+1)]

for prime in prime_list:
    for elem in range(prime*2, max(prime_list)+1, prime):
        if elem in prime_list:
            prime_list.remove(elem)
"""   
, number=10))