Monty Hall problem simulation

monty-hall.py

# monty hall problem simulation https://en.wikipedia.org/wiki/Monty_Hall_problem

import random

ITERATIONS = 10000

stick_count = 0
stick_wins = 0
switch_count = 0
switch_wins = 0

for _ in range(ITERATIONS):
	doors = ["car", "goat", "goat"]
	random.shuffle(doors)
	car_idx = doors.index("car") 
	
	# pick a random index into list doors. List indexes start at 0 and stop at len(doors)-1	
	pick_idx = random.randint(0, 2)   # 0, 1 or 2
	
	reveal_candidates = [0, 1, 2]
	reveal_candidates.remove(pick_idx)
	if car_idx != pick_idx:
	    reveal_candidates.remove(car_idx)
	reveal_idx = random.choice(reveal_candidates)
	
	if random.choice(["stick", "switch"]) == "stick":
		stick_count += 1
		if pick_idx == car_idx:
			stick_wins += 1
	else:
		switch_count += 1
		if pick_idx != car_idx:
			switch_wins += 1


stick_win_pc = stick_wins / stick_count * 100
print(f"stick win percentage: {stick_wins}/{stick_count} = {stick_win_pc:.2f}%")
switch_win_pc = switch_wins / switch_count * 100
print(f"switch win percentage: {switch_wins}/{switch_count} = {switch_win_pc:.2f}%")

run.md

$ python3 monty-hall.py 
stick win percentage: 1610/4975 = 32.36%
switch win percentage: 3271/5025 = 65.09%