21点小游戏Python详细讲解

21点是一种常见的纸牌游戏，也叫做“Blackjack”。在这个游戏中，玩家需要比庄家更靠近21分，但不能超过21分。如果玩家手中的牌点数超过21分，则玩家输掉游戏。如果庄家手中的牌点数超过21分，则庄家输掉游戏。如果玩家手中的牌点数比庄家更靠近21分，则玩家赢得游戏。

下面我们来详细讲解一下如何使用 Python 编写一个简单的 21 点游戏。

1. 初始化游戏

首先，我们需要引入随机数模块和初始化一些变量。我们需要一副牌（52张），每张牌都有一个点数和花色。点数分别为1-10、J、Q、K，花色为红桃、方块、梅花、黑桃。我们使用一个列表来存储牌的点数和花色，再使用一个列表来存储已经发出的牌。

import random

suits = ['Hearts', 'Diamonds', 'Clubs', 'Spades']
ranks = ['Ace', '2', '3', '4', '5', '6', '7', '8', '9', '10', 'Jack', 'Queen', 'King']

deck = []
for suit in suits:
    for rank in ranks:
        deck.append(f'{rank} of {suit}')
        
random.shuffle(deck)

player_hand = []
dealer_hand = []

player_score = 0
dealer_score = 0

2. 发牌

我们需要发两张牌给玩家和庄家。玩家可以看到自己的牌，但只能看到庄家的一张牌。

for i in range(2):
    player_card = deck.pop()
    player_hand.append(player_card)
    player_score += get_card_value(player_card)

    dealer_card = deck.pop()
    dealer_hand.append(dealer_card)
    dealer_score += get_card_value(dealer_card)

print(f'Player has: {player_hand} ({player_score})')
print(f'Dealer has: {dealer_hand[0]}')

3. 判断是否胜利

如果玩家发牌后就直接达到了21点，则玩家赢了游戏。如果庄家发牌后就直接达到了21点，则庄家赢了游戏。

if player_score == 21:
    print('Player wins!')
    return

if dealer_score == 21:
    print('Dealer wins!')
    return

4. 玩家操作

如果玩家没有直接达到21点，则需要询问玩家是否要继续要牌。如果玩家要牌，则再发一张牌，并计算总点数。如果玩家点数超过21点，则玩家输了游戏。

while True:
    action = input('Do you want to hit or stand? ')

    if action.lower() == 'hit':
        card = deck.pop()
        player_hand.append(card)
        player_score += get_card_value(card)
        print(f'Player has: {player_hand} ({player_score})')

        if player_score > 21:
            print('Player busts! Dealer wins!')
            return
    else:
        break

5. 庄家操作

如果玩家不再要牌后，则庄家需要继续要牌，直到庄家的点数超过17点或者爆牌。

while dealer_score < 17:
    card = deck.pop()
    dealer_hand.append(card)
    dealer_score += get_card_value(card)
    print(f'Dealer has: {dealer_hand} ({dealer_score})')

    if dealer_score > 21:
        print('Dealer busts! Player wins!')
        return

6. 判断胜负

如果玩家和庄家都没有爆牌，则比较点数大小，点数更接近21点的一方获胜。

if player_score > dealer_score:
    print('Player wins!')
elif player_score < dealer_score:
    print('Dealer wins!')
else:
    print('It\'s a tie!')

7. 完整代码

import random

suits = ['Hearts', 'Diamonds', 'Clubs', 'Spades']
ranks = ['Ace', '2', '3', '4', '5', '6', '7', '8', '9', '10', 'Jack', 'Queen', 'King']

deck = []
for suit in suits:
    for rank in ranks:
        deck.append(f'{rank} of {suit}')

random.shuffle(deck)

player_hand = []
dealer_hand = []

player_score = 0
dealer_score = 0

def get_card_value(card):
    if card.startswith('Ace'):
        return 11
    elif card.startswith('King') or card.startswith('Queen') or card.startswith('Jack'):
        return 10
    else:
        return int(card.split()[0])

for i in range(2):
    player_card = deck.pop()
    player_hand.append(player_card)
    player_score += get_card_value(player_card)

    dealer_card = deck.pop()
    dealer_hand.append(dealer_card)
    dealer_score += get_card_value(dealer_card)

print(f'Player has: {player_hand} ({player_score})')
print(f'Dealer has: {dealer_hand[0]}')

if player_score == 21:
    print('Player wins!')
elif dealer_score == 21:
    print('Dealer wins!')
else:
    while True:
        action = input('Do you want to hit or stand? ')

        if action.lower() == 'hit':
            card = deck.pop()
            player_hand.append(card)
            player_score += get_card_value(card)
            print(f'Player has: {player_hand} ({player_score})')

            if player_score > 21:
                print('Player busts! Dealer wins!')
                break
        else:
            while dealer_score < 17:
                card = deck.pop()
                dealer_hand.append(card)
                dealer_score += get_card_value(card)
                print(f'Dealer has: {dealer_hand} ({dealer_score})')

                if dealer_score > 21:
                    print('Dealer busts! Player wins!')
                    break
            else:
                if player_score > dealer_score:
                    print('Player wins!')
                elif player_score < dealer_score:
                    print('Dealer wins!')
                else:
                    print('It\'s a tie!')
                break