game_theory_test.py

gistfile1.txt

#!/usr/bin/env python3

# This is a little test of the game theory problem posed in this scene:
# https://www.youtube.com/watch?v=CYyUuIXzGgI

import random

class Door:
    GOAT = 1
    CAR = 2

    def __init__(self):
        self.selected = False

    def set_prize(self, prize):
        assert prize in [Door.GOAT, Door.CAR]
        self.prize = prize

    def set_selected(self):
        self.selected = True
    
    def unset_selected(self):
        self.selected = False

    def open(self):
        self.selected = True
        print("🐐" if (self.prize) == Door.GOAT else "🚗")

class Contestant:

    select_pick = None
    open_pick = None

    def select_door(self, doors):
        pick = random.randrange(1,3)
        doors[pick].set_selected()
        self.select_pick = doors[pick]
    
    def open_door(self, doors):
        pick = random.randrange(1,2)
        doors[pick].open()
        self.open_pick = doors[pick]

class Host:

    def set_prizes(self, doors=[]):
        doors[0].set_prize(Door.CAR)
        for i in range (1, len(doors)):
            doors[i].set_prize(Door.GOAT)
        random.shuffle(doors)


    def create_doors(self, quantity):
        doors = []
        for i in range(quantity):
            doors.append(Door())
        return doors

    def set_round_two(self, doors):
        available_doors = []
        for d in doors:
            if not d.selected:
                available_doors.append(d)
            else:
                d.unset_selected()
        for d in available_doors:
            if d.prize == Door.GOAT:
                d.open()
    
    def log_outcome(self, log, pick1, pick2, doors):
        # if stay same and win, stay_same_win
        # if stay same and lose, change_win
        # if change and lose, stay_same_win
        # if change and win, change win
        if pick1.selected:
            if pick1.prize == Door.CAR:
                log.stay_same_win()
            else:
                log.change_win()
        else:
            if pick1.prize == Door.GOAT:
                log.change_win()
            else:
                log.stay_same_win()
        

class Log:

    stay_same = 0
    change = 0

    def stay_same_win(self):
        self.stay_same += 1

    def change_win(self):
        self.change += 1

    def summary(self):
        total = self.stay_same + self.change
        print(f"Total: {total}")
        print(f"Stay Same Win: {self.stay_same/total}")
        print(f"Change Win: {self.change/total}")

def main():
    host = Host()
    log = Log()
    for i in range(1000):
        doors = host.create_doors(3)
        host.set_prizes(doors)
        contestant = Contestant()
        contestant.select_door(doors)
        host.set_round_two(doors)
        contestant.open_door(doors)
        host.log_outcome(log, contestant.select_pick, contestant.open_pick, doors)
    log.summary()

if __name__ == "__main__":
    main()