Simulation for Riddler Classic (https://fivethirtyeight.com/features/can-you-beat-the-goat-monty-hall-problem/)

01_output.txt

stay_value      0.377298
switch_value    0.500682
dtype: float64

02_riddler_monty.py

import pandas as pd
import numpy as np
import random


def create_stage():
    # Returns a list of 3 "doors", with either 'prize' or 'goat' as specified in puzzle
    num_goats = np.random.randint(0, 4)
    # print(num_goats)
    doors = []
    while num_goats > 0:
        doors.append('goat')
        num_goats -= 1

    while len(doors) < 3:
        doors.append('prize')
    random.shuffle(doors)
    return doors


if __name__ == '__main__':
    results = []
    for i in range(1, 100000):
        doors = create_stage()

        # Contestant always chooses door #1 (or rather door 0)
        contestant_chosen = doors.pop()
        # print(contestant_chosen)

        # If monty is able, he will open a door with a goat (remove from the list of remaining doors)
        if 'goat' in doors:
            # print(doors)
            doors.remove('goat')
            # print(len(doors))
            results.append({'contestant': contestant_chosen, 'switch': doors[0]})
            # save the contestants door and the door if you were to switch
        # else:
        #     print('monty cant open another door...')
        
    results_df = pd.DataFrame(results)
    results_df['stay_value'] = results_df['contestant'] == 'prize'
    results_df['switch_value'] = results_df['switch'] == 'prize'
    print(results_df.mean(axis=0))