decopy.py

from time import time
from random import random

# A "decorator" -- a function that:
#    - takes a function as its arg
#    - returns a "wrapped version" of that function
#
# In this case: the wrapped version runs the real function,
# but keeps track of how long it took to run.


def timeit(fn):
    def wrapper(*args, **kwargs):
        start_time = time()
        result = fn(*args, **kwargs)
        time_in_msec = int((time() - start_time) * 1000)
        print(fn.__name__, f'({time_in_msec} ms)', args, result)
        return result

    return wrapper


# An example of a function we'd like to profile: to make it slow, give
# it a big `n` and a tiny `chance`

def slowish_thing(n, chance):
    for i in range(n):
        if random() < chance:
            return True

    return False


# A "wrapped" version of our function: we'll just reassign it to the same
# name --- now when you call this function, it will run timeit wrapped
# function, which ultimately calls the real slowish_thing

slowish_thing = timeit(slowish_thing)


print(slowish_thing(1000000, 0.00000001))


# same idea, but nicer syntax using a decorator

@timeit
def slowish_thing2(n, chance):
    for i in range(n):
        if random() < chance:
            return True

    return False


print(slowish_thing2(1000000, 0.00000001))