如何用python写一个贪吃蛇游戏

以下是一个简单的贪吃蛇游戏实现，使用Python的pygame库：

import pygame
import random

# 初始化pygame
pygame.init()

# 设置游戏屏幕大小
screen_width = 480
screen_height = 480
screen = pygame.display.set_mode((screen_width, screen_height))

# 设置游戏标题
pygame.display.set_caption('贪吃蛇')

# 设置游戏时钟
clock = pygame.time.Clock()

# 定义颜色
white = (255, 255, 255)
black = (0, 0, 0)
red = (255, 0, 0)
green = (0, 255, 0)

# 定义贪吃蛇块的大小
block_size = 10

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

# 定义函数，用于输出文字
def print_text(msg, color, x, y):
    text = font.render(msg, True, color)
    screen.blit(text, [x, y])

# 定义函数，用于绘制贪吃蛇
def draw_snake(snake_list):
    for x,y in snake_list:
        pygame.draw.rect(screen, green, [x, y, block_size, block_size])

# 定义主函数
def main():
    game_over = False

    # 定义贪吃蛇初始位置和长度
    snake_x = screen_width / 2
    snake_y = screen_height / 2
    snake_list = []
    snake_length = 1

    # 定义食物初始位置
    food_x = round(random.randrange(0, screen_width - block_size) / 10.0) * 10.0
    food_y = round(random.randrange(0, screen_height - block_size) / 10.0) * 10.0

    # 定义贪吃蛇移动的初始方向
    direction = 'right'
    change_direction = direction

    # 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:
                    change_direction = 'left'
                elif event.key == pygame.K_RIGHT:
                    change_direction = 'right'
                elif event.key == pygame.K_UP:
                    change_direction = 'up'
                elif event.key == pygame.K_DOWN:
                    change_direction = 'down'

        # 判断是否改变方向
        if change_direction == 'left' and direction != 'right':
            direction = 'left'
        elif change_direction == 'right' and direction != 'left':
            direction = 'right'
        elif change_direction == 'up' and direction != 'down':
            direction = 'up'
        elif change_direction == 'down' and direction != 'up':
            direction = 'down'

        # 移动贪吃蛇
        if direction == 'left':
            snake_x -= block_size
        elif direction == 'right':
            snake_x += block_size
        elif direction == 'up':
            snake_y -= block_size
        elif direction == 'down':
            snake_y += block_size

        # 判断是否吃到食物
        if snake_x == food_x and snake_y == food_y:
            food_x = round(random.randrange(0, screen_width - block_size) / 10.0) * 10.0
            food_y = round(random.randrange(0, screen_height - block_size) / 10.0) * 10.0
            snake_length += 1

        # 绘制背景
        screen.fill(white)

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

        # 绘制贪吃蛇
        snake_head = [snake_x, snake_y]
        snake_list.append(snake_head)
        if len(snake_list) > snake_length:
            del snake_list[0]
        for segment in snake_list[:-1]:
            if segment == snake_head:
                game_over = True
        draw_snake(snake_list)

        # 输出分数
        print_text('Score: ' + str(snake_length - 1), black, 10, 10)

        # 更新屏幕
        pygame.display.update()

        # 设置游戏帧率
        clock.tick(10)

    # 退出pygame
    pygame.quit()

# 调用主函数
if __name__ == '__main__':
    main()

运行代码后，即可开始游戏。玩家通过方向键控制贪吃蛇的移动，吃到食物分数加1，每撞到自己一次分数减1，当分数小于0时游戏结束。