用python 写一个 贪吃蛇小游戏

好的，我可以帮你用 Python 写一个简单的贪吃蛇小游戏。以下是代码：

import pygame
import random

# 初始化 Pygame
pygame.init()

# 定义窗口大小和背景颜色
WINDOW_WIDTH = 500
WINDOW_HEIGHT = 500
BACKGROUND_COLOR = (255, 255, 255)

# 创建游戏窗口
game_window = pygame.display.set_mode((WINDOW_WIDTH, WINDOW_HEIGHT))
pygame.display.set_caption('贪吃蛇小游戏')

# 定义贪吃蛇和食物的颜色和大小
SNAKE_COLOR = (0, 255, 0)
FOOD_COLOR = (255, 0, 0)
BLOCK_SIZE = 20

# 定义游戏帧率和时钟
FPS = 10
clock = pygame.time.Clock()

# 定义游戏结束函数
def game_over():
    font = pygame.font.SysFont(None, 50)
    text = font.render('游戏结束！', True, (255, 0, 0))
    game_window.blit(text, (WINDOW_WIDTH/2 - text.get_width()/2, WINDOW_HEIGHT/2 - text.get_height()/2))
    pygame.display.update()
    pygame.time.delay(3000)
    pygame.quit()
    quit()

# 定义绘制贪吃蛇和食物的函数
def draw_snake(snake_block, snake_list):
    for block in snake_list:
        pygame.draw.rect(game_window, SNAKE_COLOR, [block[0], block[1], snake_block, snake_block])

def draw_food():
    pygame.draw.rect(game_window, FOOD_COLOR, [food_x, food_y, BLOCK_SIZE, BLOCK_SIZE])

# 定义主函数
def main():
    # 定义贪吃蛇初始位置和长度
    snake_x = WINDOW_WIDTH / 2
    snake_y = WINDOW_HEIGHT / 2
    snake_list = []
    snake_length = 1

    # 定义贪吃蛇移动方向和速度
    velocity_x = 0
    velocity_y = 0
    snake_speed = 20

    # 定义食物初始位置
    global food_x, food_y
    food_x = round(random.randrange(0, WINDOW_WIDTH - BLOCK_SIZE) / 20.0) * 20.0
    food_y = round(random.randrange(0, WINDOW_HEIGHT - BLOCK_SIZE) / 20.0) * 20.0

    # 游戏循环
    game_over_flag = False
    while not game_over_flag:

        # 处理事件
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                game_over_flag = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    velocity_x = -snake_speed
                    velocity_y = 0
                elif event.key == pygame.K_RIGHT:
                    velocity_x = snake_speed
                    velocity_y = 0
                elif event.key == pygame.K_UP:
                    velocity_y = -snake_speed
                    velocity_x = 0
                elif event.key == pygame.K_DOWN:
                    velocity_y = snake_speed
                    velocity_x = 0

        # 移动贪吃蛇
        snake_x += velocity_x
        snake_y += velocity_y

        # 判断是否