Monty Hall

monty_hall.py

import random

cars, donkeys = 0, 0
trials = 10000
doors = ['a', 'b', 'c']
for i in range(trials):
    # place the car behind a random door
    car_door = random.choice(doors)
    # choose first door at random
    first_choice = random.choice(doors)
    # reveal a donkey from a random door that is not the first choice
    revealed_donkey = random.choice(
        [d for d in doors if d != first_choice and d != car_door]
        )[0]
    # switch door to the only remaining door
    second_choice = [d for d in doors \
                     if d != first_choice and d != revealed_donkey][0]
    if second_choice == car_door:
        # final choice is car
        cars += 1
    else:
        # final choice is donkey
        donkeys += 1
# prints something like "cars: 6765 donkeys: 3235 car %: 0.6765
print 'cars:', cars, 'donkeys:', donkeys, 'car %:', cars/float(donkeys + cars)