Monty Hall Simulator

montyhall.py

#!/usr/bin/env python3 
import random
import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
NUM_ROUNDS = 100000

def _get_doors():
    doors = [False, False, False]
    doors[random.randrange(0, len(doors))] = True
    return doors

def _switch_door(doors, player_choice, door_with_goat):
    potential_doors = set(range(0, len(doors)))
    potential_doors.remove(player_choice)
    potential_doors.remove(door_with_goat)
    return random.choice(tuple(potential_doors))

def _reveal_goat(doors, player_choice):
    potential_doors = set(range(0, len(doors)))
    potential_doors.remove(player_choice)
    while True:
        potential_reveal = random.choice(tuple(potential_doors))
        if not doors[potential_reveal]:
            return potential_reveal
        else:
            potential_doors.remove(potential_reveal)


def play_monty_hall(switch):
    '''
    return true if game won
    '''
    doors = _get_doors()
    logger.debug('There are {} doors'.format(len(doors)))
    player_choice = random.randrange(0, len(doors))
    logger.debug('Player has chosen door #{}'.format(player_choice + 1))
    door_with_goat = _reveal_goat(doors, player_choice)
    logger.debug('Monty has revealed door #{} to have a goat'.format(door_with_goat + 1))
    if switch:
        player_choice = _switch_door(doors, player_choice, door_with_goat)
        logger.debug('Player has switched to door #{}'.format(player_choice +1))
    else:
        logger.debug('Player has chosen to stick with door #{}'.format(player_choice +1))
    result = doors[player_choice]
    if result:
        logger.debug('Player has won the car! :-D')
    else:
        logger.debug('Player got a goat :-(')
    return result


def play_iterated_monty_hall(switch, num_rounds):
    '''
    returns how many rounds you won playing X rounds
    '''
    return len(list(filter(lambda x: x, [play_monty_hall(switch) for _ in range(NUM_ROUNDS)]))) 

def main():
    with_switching = play_iterated_monty_hall(True, NUM_ROUNDS)
    with_sticking = play_iterated_monty_hall(False, NUM_ROUNDS)
    print('With switching you won {}% of games'.format((with_switching/NUM_ROUNDS)*100))
    print('With sticking you won {}% of games'.format((with_sticking/NUM_ROUNDS)*100))


if __name__ == '__main__':
    main()

Result
With switching you won 66.764% of games
With sticking you won 33.324% of games