Monty Hall problem in Python.

monty_hall.py

from random import randint

def evaluate_a_monty_hall_scenario(switch=False):
    options = set([1, 2, 3])
    car = randint( 1, 3)
    pick = randint( 1, 3)
    opened = list( options.difference( set([car])).difference( set([pick])))[0]
    closed = list( options.difference( set([pick])).difference( set([opened])))[0]
    if switch:
        pick = closed
    return car == pick


def evaluate_monty_hall_problem( switch=False):
    trials = 10000
    count = 0
    for i in range( 0, trials):
        result = evaluate_a_monty_hall_scenario( switch)
        if result:
            count += 1
    return float( count) / trials

evaluate_monty_hall_problem(True)