monty_hall.py

import random


donkey = 0
car = 10  # car is worth more than a donkey
prizes = [car, donkey, donkey]  # there's always exactly one car
N = 1000000


def pick_a_door(prizes):
    random.shuffle(prizes)
    my_pick, *other_doors = prizes
    return [my_pick, other_doors]


def keep_or_swap(my_picks, keep=False):
    if keep:
        return my_picks[0]
    else:
        # if you switch, and one of the other doors had the car, you
        # will definitely get it, so you get the max() of those two doors
        return max(my_picks[1])


print(sum([keep_or_swap(pick_a_door(prizes)) for i in range(N)]) / N)

print(sum([keep_or_swap(pick_a_door(prizes), keep=True) for i in range(N)]) / N)