用Python写一个贪吃蛇小游戏，请给出代码

以下是一个简单的贪吃蛇小游戏的 Python 代码：

import pygame
import random

# 初始化 Pygame
pygame.init()

# 设置游戏窗口大小和标题
window_width = 800
window_height = 600
window = pygame.display.set_mode((window_width, window_height))
pygame.display.set_caption("Snake Game")

# 设置颜色
white = (255, 255, 255)
black = (0, 0, 0)
green = (0, 255, 0)
red = (255, 0, 0)

# 设置字体
font = pygame.font.SysFont(None, 25)

# 设置蛇的初始位置和大小
snake_block_size = 10
snake_list = []
snake_length = 1
snake_head_x = window_width / 2
snake_head_y = window_height / 2
snake_x_change = 0
snake_y_change = 0

# 设置食物的初始位置和大小
food_block_size = 10
food_x = round(random.randrange(0, window_width - food_block_size) / 10.0) * 10.0
food_y = round(random.randrange(0, window_height - food_block_size) / 10.0) * 10.0

# 设置游戏结束的变量
game_over = False

# 定义函数：显示分数
def show_score(score):
    score_text = font.render("Score: " + str(score), True, white)
    window.blit(score_text, [0, 0])

# 定义函数：显示蛇
def draw_snake(snake_block_size, snake_list):
    for x in snake_list:
        pygame.draw.rect(window, green, [x[0], x[1], snake_block_size, snake_block_size])

# 游戏循环
while not game_over:
    # 处理事件
    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:
                snake_x_change = -snake_block_size
                snake_y_change = 0
            elif event.key == pygame.K_RIGHT:
                snake_x_change = snake_block_size
                snake_y_change = 0
            elif event.key == pygame.K_UP:
                snake_y_change = -snake_block_size
                snake_x_change = 0
            elif event.key == pygame.K_DOWN:
                snake_y_change = snake_block_size
                snake_x_change = 0

    # 移动蛇的位置
    snake_head_x += snake_x_change
    snake_head_y += snake_y_change

    # 如果蛇吃到了食物，增加分数，重新生成食物，增加蛇的长度
    if snake_head_x == food_x and snake_head_y == food_y:
        food_x = round(random.randrange(0, window_width - food_block_size) / 10.0) * 10.0
        food_y = round(random.randrange(0, window_height - food_block_size) / 10.0) * 10.0
        snake_length += 1

    # 添加蛇头的位置到蛇的列表中
    snake_head = []
    snake_head.append(snake_head_x)
    snake_head.append(snake_head_y)
    snake_list.append(snake_head)

    # 如果蛇的长度大于最大长度，删除蛇尾的位置
    if len(snake_list) > snake_length:
        del snake_list[0]

    # 如果蛇的头部撞到了边界，游戏结束
    if snake_head_x >= window_width or snake_head_x < 0 or snake_head_y >= window_height or snake_head_y < 0:
        game_over = True

    # 如果蛇的头部撞到了蛇的身体，游戏结束
    for x in snake_list[:-1]:
        if x == snake_head:
            game_over = True

    # 清空窗口
    window.fill(black)

    # 绘制食物
    pygame.draw.rect(window, red, [food_x, food_y, food_block_size, food_block_size])

    # 绘制蛇
    draw_snake(snake_block_size, snake_list)

    # 显示分数
    show_score(snake_length - 1)

    # 刷新窗口
    pygame.display.update()

# 退出 Pygame
pygame.quit()

这个代码使用 Pygame 库创建了一个游戏窗口，并在其中实现了贪吃蛇的基本逻辑。运行代码即可开始游戏。