用python写一个贪吃蛇的游戏代码

好的，下面是一个简单的Python贪吃蛇游戏代码示例，使用Python 3和Pygame库：

import pygame
import random

# 初始化Pygame
pygame.init()

# 定义游戏画面大小
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600

# 创建游戏画面
screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
pygame.display.set_caption('贪吃蛇')

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

# 定义贪吃蛇和食物的大小
BLOCK_SIZE = 20

# 定义字体
font = pygame.font.SysFont(None, 25)

def snake(block_size, snake_list):
    for x_y in snake_list:
        pygame.draw.rect(screen, GREEN, [x_y[0], x_y[1], block_size, block_size])

def message_to_screen(msg, color):
    screen_text = font.render(msg, True, color)
    screen.blit(screen_text, [SCREEN_WIDTH/2, SCREEN_HEIGHT/2])

# 游戏循环
def gameLoop():
    gameExit = False
    gameOver = False

    # 定义贪吃蛇初始位置和长度
    lead_x = SCREEN_WIDTH/2
    lead_y = SCREEN_HEIGHT/2
    lead_x_change = 0
    lead_y_change = 0
    snake_list = []
    snake_length = 1

    # 定义食物初始位置
    randAppleX = round(random.randrange(0, SCREEN_WIDTH - BLOCK_SIZE) / BLOCK_SIZE) * BLOCK_SIZE
    randAppleY = round(random.randrange(0, SCREEN_HEIGHT - BLOCK_SIZE) / BLOCK_SIZE) * BLOCK_SIZE

    while not gameExit:

        while gameOver == True:
            screen.fill(WHITE)
            message_to_screen("游戏结束，按Q退出或者按C重新开始游戏", RED)
            pygame.display.update()

            for event in pygame.event.get():
                if event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_q:
                        gameExit = True
                        gameOver = False
                    elif event.key == pygame.K_c:
                        gameLoop()

        # 处理键盘事件
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                gameExit = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    lead_x_change = -BLOCK_SIZE
                    lead_y_change = 0
                elif event.key == pygame.K_RIGHT:
                    lead_x_change = BLOCK_SIZE
                    lead_y_change = 0
                elif event.key == pygame.K_UP:
                    lead_y_change = -BLOCK_SIZE
                    lead_x_change = 0
                elif event.key == pygame.K_DOWN:
                    lead_y_change = BLOCK_SIZE
                    lead_x_change = 0

        # 判断贪吃蛇是否撞到墙
        if lead_x >= SCREEN_WIDTH or lead_x < 0 or lead_y >= SCREEN_HEIGHT or lead_y < 0:
            gameOver = True

        # 更新贪吃蛇的位置
        lead_x += lead_x_change
        lead_y += lead_y_change

        # 绘制背