生成一段python代码，实现贪吃蛇

很高兴回答你的问题。以下是一段简单的 Python 代码，可以实现贪吃蛇游戏：

import pygame
import random

# 初始化 Pygame
pygame.init()

# 定义颜色
white = (255, 255, 255)
black = (, , )
red = (255, , )

# 定义游戏窗口大小
width = 600
height = 400

# 创建游戏窗口
screen = pygame.display.set_mode((width, height))
pygame.display.set_caption("贪吃蛇")

# 定义蛇的初始位置和大小
snake_block = 10
snake_speed = 15
x1 = width / 2
y1 = height / 2

# 定义蛇的移动方向
x1_change = 
y1_change = 

# 定义食物的初始位置
foodx = round(random.randrange(, width - snake_block) / 10.) * 10.
foody = round(random.randrange(, height - snake_block) / 10.) * 10.

# 定义字体
font_style = pygame.font.SysFont(None, 30)

# 定义显示分数的函数
def message(msg, color):
    mesg = font_style.render(msg, True, color)
    screen.blit(mesg, [width / 6, height / 6])

# 游戏循环
game_over = False
while not game_over:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            game_over = True
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                x1_change = -snake_block
                y1_change = 
            elif event.key == pygame.K_RIGHT:
                x1_change = snake_block
                y1_change = 
            elif event.key == pygame.K_UP:
                y1_change = -snake_block
                x1_change = 
            elif event.key == pygame.K_DOWN:
                y1_change = snake_block
                x1_change = 

    # 判断蛇是否撞墙
    if x1 >= width or x1 <  or y1 >= height or y1 < :
        game_over = True

    # 移动蛇的位置
    x1 += x1_change
    y1 += y1_change

    # 绘制蛇和食物
    screen.fill(black)
    pygame.draw.rect(screen, red, [foodx, foody, snake_block, snake_block])
    pygame.draw.rect(screen, white, [x1, y1, snake_block, snake_block])

    # 判断蛇是否吃到食物
    if x1 == foodx and y1 == foody:
        print("Yummy!!")
    pygame.display.update()

    # 显示分数
    message("Your Score: ", white)

    # 控制游戏速度
    clock = pygame.time.Clock()
    clock.tick(snake_speed)

# 退出 Pygame
pygame.quit()