写一段python代码实现贪吃蛇游戏

好的，以下是一个简单的贪吃蛇游戏的Python代码：

import pygame
import random

# 游戏窗口大小
WINDOW_WIDTH = 640
WINDOW_HEIGHT = 480

# 贪吃蛇每个方块的大小
BLOCK_SIZE = 20

# 初始化pygame
pygame.init()

# 创建游戏窗口
window = pygame.display.set_mode((WINDOW_WIDTH, WINDOW_HEIGHT))
pygame.display.set_caption("贪吃蛇")

# 定义颜色
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)

# 贪吃蛇类
class Snake:
    def __init__(self):
        # 初始位置在屏幕中央
        self.x = WINDOW_WIDTH // 2
        self.y = WINDOW_HEIGHT // 2
        # 初始方向向右
        self.direction = "right"
        # 初始长度为3
        self.length = 3
        # 初始身体坐标列表
        self.body = []
        for i in range(self.length):
            self.body.append((self.x - i * BLOCK_SIZE, self.y))

    # 向左移动
    def move_left(self):
        self.x -= BLOCK_SIZE
        self.direction = "left"

    # 向右移动
    def move_right(self):
        self.x += BLOCK_SIZE
        self.direction = "right"

    # 向上移动
    def move_up(self):
        self.y -= BLOCK_SIZE
        self.direction = "up"

    # 向下移动
    def move_down(self):
        self.y += BLOCK_SIZE
        self.direction = "down"

    # 移动一步
    def move(self):
        if self.direction == "left":
            self.move_left()
        elif self.direction == "right":
            self.move_right()
        elif self.direction == "up":
            self.move_up()
        elif self.direction == "down":
            self.move_down()

        # 在头部添加新坐标
        self.body.insert(0, (self.x, self.y))

        # 如果长度超过了蛇身体的实际长度，则删除尾部坐标
        if len(self.body) > self.length:
            self.body.pop()

    # 绘制蛇
    def draw(self):
        for i, (x, y) in enumerate(self.body):
            # 头部用红色
            if i == 0:
                pygame.draw.rect(window, RED, (x, y, BLOCK_SIZE, BLOCK_SIZE))
            # 身体用绿色
            else:
                pygame.draw.rect(window, GREEN, (x, y, BLOCK_SIZE, BLOCK_SIZE))

# 食物类
class Food:
    def __init__(self):
        # 随机生成一个坐标
        self.x = random.randint(0, WINDOW_WIDTH - BLOCK_SIZE)
        self.y = random.randint(0, WINDOW_HEIGHT - BLOCK_SIZE)

    # 绘制食物
    def draw(self):
        pygame.draw.rect(window, WHITE, (self.x, self.y, BLOCK_SIZE, BLOCK_SIZE))

# 创建贪吃蛇和食物
snake = Snake()
food = Food()

# 游戏循环
while True:
    # 处理事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            quit()
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT and snake.direction != "right":
                snake.direction = "left"
            elif event.key == pygame.K_RIGHT and snake.direction != "left":
                snake.direction = "right"
            elif event.key == pygame.K_UP and snake.direction != "down":
                snake.direction = "up"
            elif event.key == pygame.K_DOWN and snake.direction != "up":
                snake.direction = "down"

    # 移动贪吃蛇
    snake.move()

    # 判断是否吃到了食物
    if snake.body[0][0] == food.x and snake.body[0][1] == food.y:
        # 食物重新生成
        food = Food()
        # 蛇长度加1
        snake.length += 1

    # 绘制游戏界面
    window.fill(BLACK)
    snake.draw()
    food.draw()
    pygame.display.update()

    # 判断是否撞墙或撞到自己
    if snake.body[0][0] < 0 or snake.body[0][0] >= WINDOW_WIDTH or snake.body[0][1] < 0 or snake.body[0][1] >= WINDOW_HEIGHT:
        pygame.quit()
        quit()
    for i in range(1, len(snake.body)):
        if snake.body[0][0] == snake.body[i][0] and snake.body[0][1] == snake.body[i][1]:
            pygame.quit()
            quit()

    # 控制游戏速度
    pygame.time.Clock().tick(10)

这是一个比较简单的实现，你可以根据自己的需求来修改。