用python写一个贪吃蛇小游戏。

下面是一个简单的贪吃蛇小游戏的示例代码，使用Python的pygame库实现：

import pygame
import random

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

# 设置窗口大小和格子大小
window_width, window_height = 800, 600
grid_size = 20

# 初始化pygame
pygame.init()

# 创建窗口
window_size = (window_width, window_height)
window = pygame.display.set_mode(window_size)
pygame.display.set_caption("贪吃蛇游戏")

# 游戏时钟
clock = pygame.time.Clock()

# 蛇的初始位置和速度
snake_x = window_width // 2
snake_y = window_height // 2
snake_speed_x = 0
snake_speed_y = 0

# 蛇身体的列表
snake_body = []
snake_length = 1

# 食物的初始位置
food_x = random.randint(0, (window_width - grid_size) // grid_size) * grid_size
food_y = random.randint(0, (window_height - grid_size) // grid_size) * grid_size

# 游戏结束标志
game_over = False

while not game_over:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            game_over = True
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                snake_speed_x = -grid_size
                snake_speed_y = 0
            elif event.key == pygame.K_RIGHT:
                snake_speed_x = grid_size
                snake_speed_y = 0
            elif event.key == pygame.K_UP:
                snake_speed_x = 0
                snake_speed_y = -grid_size
            elif event.key == pygame.K_DOWN:
                snake_speed_x = 0
                snake_speed_y = grid_size

    # 更新蛇的位置
    snake_x += snake_speed_x
    snake_y += snake_speed_y

    # 判断蛇是否吃到食物
    if snake_x == food_x and snake_y == food_y:
        food_x = random.randint(0, (window_width - grid_size) // grid_size) * grid_size
        food_y = random.randint(0, (window_height - grid_size) // grid_size) * grid_size
        snake_length += 1

    # 判断蛇是否撞到墙壁或自己的身体
    if (snake_x < 0 or snake_x >= window_width or
            snake_y < 0 or snake_y >= window_height or
            (snake_x, snake_y) in snake_body):
        game_over = True

    # 更新蛇身体的列表
    snake_body.append((snake_x, snake_y))
    if len(snake_body) > snake_length:
        del snake_body[0]

    # 清除窗口
    window.fill(BLACK)

    # 绘制蛇的身体和食物
    for body_part in snake_body:
        pygame.draw.rect(window, GREEN, (body_part[0], body_part[1], grid_size, grid_size))
    pygame.draw.rect(window, RED, (food_x, food_y, grid_size, grid_size))

    # 更新窗口显示
    pygame.display.flip()

    # 控制游戏帧率
    clock.tick(10)

# 退出游戏
pygame.quit()

这个示例代码实现了一个简单的贪吃蛇小游戏。玩家可以使用上下左右键来控制蛇的移动，目标是吃到食物并尽量避免撞到墙壁或自己的身体。游戏窗口大小、格子大小、蛇的速度等参数可以根据需要进行调整。