snake.py

import pygame
import random

pygame.init()
screen = pygame.display.set_mode((800,800))
clock = pygame.time.Clock()
pygame.event.set_allowed([pygame.QUIT, pygame.KEYDOWN, pygame.KEYUP])

white = (255,255,255)
black = (0,0,0)
red = (255,0,0)

comicsans = pygame.font.SysFont('comicsans', 50)

snake = [(400,400)]
v = (0,0)
size = 40
eat = True

done = False
while not done:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True
    
    if eat:
        while True:
            food = (random.randrange(800//size)*size, random.randrange(800//size)*size)
            if food not in snake:
                break
        eat = False

    pressed = pygame.key.get_pressed()
    if pressed[pygame.K_UP] or pressed[pygame.K_w]:
        v=(0,-size)
    elif pressed[pygame.K_DOWN] or pressed[pygame.K_s]:
        v=(0,size)
    elif pressed[pygame.K_LEFT] or pressed[pygame.K_a]:
        v=(-size,0)
    elif pressed[pygame.K_RIGHT] or pressed[pygame.K_d]:
        v=(size,0)

    snake.append((snake[-1][0]+v[0], snake[-1][1]+v[1]))

    if not (0<=snake[-1][0]<=800 and 0<=snake[-1][1]<=800) or snake[-1] in snake[:-2]:
        done = True
    
    if snake[-1]==food:
        eat = True
    elif v:
        snake.pop(0)

    screen.fill(black)

    pygame.draw.rect(screen, red, pygame.Rect(food[0]+size//4,food[1]+size//4,size//2,size//2))
    for x,y in snake:
        pygame.draw.rect(screen, white, pygame.Rect(x,y,size,size))
    
    text = comicsans.render(str(len(snake)), True, white)
    textbox = text.get_rect()
    textbox.center = (400,100)
    screen.blit(text, textbox)

    clock.tick(10)
    pygame.display.flip()