用python做一个贪吃蛇程序

好的，以下是一个基于 Python 的简单贪吃蛇程序：

import pygame
import random

# 初始化pygame
pygame.init()

# 设置窗口大小和标题
width, height = 500, 500
screen = pygame.display.set_mode((width, height))
pygame.display.set_caption("贪吃蛇")

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

# 定义蛇和食物的大小
block_size = 10

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

# 定义函数，用于显示消息
def message_to_screen(msg, color):
    screen_text = font.render(msg, True, color)
    screen.blit(screen_text, [width/2, height/2])

# 定义贪吃蛇类
class Snake:
    def __init__(self):
        self.x = width/2
        self.y = height/2
        self.x_change = 0
        self.y_change = 0
        self.body = []
        self.length = 1

    def draw(self):
        for x,y in self.body:
            pygame.draw.rect(screen, green, [x, y, block_size, block_size])

    def move(self):
        self.x += self.x_change
        self.y += self.y_change
        self.body.append((self.x, self.y))
        if len(self.body) > self.length:
            del self.body[0]

    def change_direction(self, direction):
        if direction == "LEFT":
            self.x_change = -block_size
            self.y_change = 0
        elif direction == "RIGHT":
            self.x_change = block_size
            self.y_change = 0
        elif direction == "UP":
            self.y_change = -block_size
            self.x_change = 0
        elif direction == "DOWN":
            self.y_change = block_size
            self.x_change = 0

# 定义食物类
class Food:
    def __init__(self):
        self.x = round(random.randrange(0, width-block_size)/10.0)*10.0
        self.y = round(random.randrange(0, height-block_size)/10.0)*10.0

    def draw(self):
        pygame.draw.rect(screen, red, [self.x, self.y, block_size, block_size])

# 创建