python - 蒙蒂霍尔模拟出了问题(python)

Question

#
# Monty Hall Problem Simulation
# Author: Ryan Sturmer
#

import random

def play_round(doors, switch):

    # Choose the location of the car
    car = random.randint(1, doors)

    # Contestant chooses a door 
    initial_choice = random.randint(1, doors)

    # Monty opens ALL the other doors except one
    if initial_choice != car:
        monty_leaves = car # If the car wasn't chosen, Monty is forced to reveal its location
    else:
        while True:
            monty_leaves = random.randint(1, doors)
            if monty_leaves != initial_choice:
                break

    # monty_leaves is now the door that Monty DIDN'T open
    if switch:
        final_choice = monty_leaves
    else:
        final_choice = initial_choice

    victory = (final_choice == car)

    return victory, initial_choice, final_choice, car

def simulation(iterations, doors=3):
    games_won_switch = 0
    games_won_noswitch = 0
    for i in range(iterations):
        won_game, intial_choice, final_choice, car = play_round(doors, False)
        if(won_game):
            games_won_noswitch += 1
        won_game, intial_choice, final_choice, car = play_round(doors, True)
        if(won_game):
            games_won_switch += 1

    print ""
    print "            Monty Hall Simulation"
    print "---------------------------------------------"
    print "                        Iterations: %d" % iterations
    print "    Games won when switching doors: %d (%g%%)" % (games_won_switch, 100*float(games_won_switch)/float(iterations))
    print "Games won when NOT switching doors: %d (%g%%)" % (games_won_noswitch, 100*float(games_won_noswitch)/float(iterations))

================================================== =============================

我从github上找到了这段代码。当我运行此代码时，games_won_switch 和 games_won_noswitch 的总和不等于迭代。(例如，如果我设置迭代 1,000 -> 它会显示 996、1,001、1,008，而不是精确的 1,000)

我该如何解决这个问题？

Answer 1

代码没有错误；它运行模拟两次:

一次是玩家选择每次换门，另一次是玩家选择从不换门。然后它会打印两次模拟的结果。

结果来自独立模拟。

for i in range(iterations):

    # Sim with player choose to open the door each time
    won_game, intial_choice, final_choice, car = play_round(doors, False) 
    if(won_game):
        games_won_noswitch += 1

    # Sim with player choose NEVER to open the door
    won_game, intial_choice, final_choice, car = play_round(doors, True)
    if(won_game):
        games_won_switch += 1

因此，由于 sim(open=True) 不是 (1 - sim(open=False))，而是两组模拟的结果，因此加法结果的总和可能无法精确地等于试验次数。