索引列表E

Question

我有一个问题，我甚至不知道问题是什么，但我的代码，但我已经有了第一个问题修复，然后这发生了。请帮我修一下，或者找出问题所在

import pygame
import time
import random

pygame.init()

white = (255,255,255)
black = (0,0,0)
red = (255,0,0)
orange = (255,127,0)
yellow = (255,255,0)
green = (0,255,0)
blue = (0,0,255)
purple = (143,0,255)
dark_green = (0,155,0)

display_width = 800
display_height = 600

gameDisplay = pygame.display.set_mode((display_width,display_height))
pygame.display.set_caption("Slither")

img = pygame.image.load(r"C:\Users\BJBGaming\Desktop\snakehead.png")

clock = pygame.time.Clock()

block_size = 20
FPS = 15

font = pygame.font.SysFont(None, 25)

def snake(block_size, snakelist):

    print(snakelist)
    gameDisplay.blit(img,(snakelist[-1][0], snakelist[-1][1]))

    for XnY in snakelist[:-1]:
        pygame.draw.rect(gameDisplay, dark_green, [XnY[0],XnY[1],block_size,block_size])

def text_objects(text,color):
    textSurface = font.render(text, True, color)
    return textSurface, textSurface.get_rect()


def message_to_screen(msg,color):
    textSurf, textRect = text_objects(msg,color)
    #screen_text = font.render(msg, True, color)
    #gameDisplay.blit(screen_text, [display_width/2, display_height/2])
    textRect.center = (display_width / 2), (display_height / 2)
    gameDisplay.blit(textSurf, textRect)


def gameLoop():
    gameExit = False
    gameOver = False

    lead_x = display_width/2
    lead_y = display_height/2

    lead_x_change = 0
    lead_y_change = 0

    snakeList = []
    snakeLength = 0

    randAppleX = round(random.randrange(0, display_width-block_size))#/10.0)*10.0
    randAppleY = round(random.randrange(0, display_height-block_size))#/10.0)*10.0

    while not gameExit:

        while gameOver == True:
            gameDisplay.fill(white)
            message_to_screen("Game over, press Q to play again ot W to quit", red)
            pygame.display.update()

            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    gameExit = True
                    gameOver = False
                if event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_w:
                        gameExit = True
                        gameOver = False
                    if event.key == pygame.K_q:
                        gameLoop()

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                gameExit = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    lead_x_change = -block_size
                    lead_y_change = 0
                elif event.key == pygame.K_RIGHT:
                    lead_x_change = block_size
                    lead_y_change = 0

                elif event.key == pygame.K_UP:
                    lead_y_change = -block_size
                    lead_x_change = 0
                elif event.key == pygame.K_DOWN:
                    lead_y_change = block_size
                    lead_x_change = 0

        if lead_x >= display_width or lead_x < 0 or lead_y >= display_height or lead_y < 0:
            gameOver = True



        lead_x += lead_x_change
        lead_y += lead_y_change

        gameDisplay.fill(white)

        AppleThickness = 30
        pygame.draw.rect(gameDisplay, red, [randAppleX, randAppleY, AppleThickness, AppleThickness])


        snakeHead = []
        snakeHead.append(lead_x)
        snakeHead.append(lead_y)
        snakeList.append(snakeHead)
        snake(block_size, snakeList)

        if len (snakeList) > snakeLength:
            del snakeList [0]

        for eachSegment in snakeList[:-1]:
            if eachSegment == snakeHead:
                gameOver = True

        snake(block_size, snakeList)


        pygame.display.update()

##        if lead_x >= randAppleX and lead_x <= randAppleX + AppleThickness:
##            if lead_y >= randAppleY and lead_y <= randAppleY + AppleThickness:
##                randAppleX = round(random.randrange(0, display_width-block_size))#/10.0)*10.0
##                randAppleY = round(random.randrange(0, display_height-block_size))#/10.0)*10.0
##                snakeLength += 1

        if lead_x > randAppleX and lead_x < randAppleX + AppleThickness or lead_x + block_size > randAppleX and lead_x + block_size < randAppleX + AppleThickness:

            if lead_y > randAppleY and lead_y < randAppleY + AppleThickness or lead_y + block_size > randAppleY and lead_y + block_size < randAppleY + AppleThickness:
                randAppleX = round(random.randrange(0, display_width-block_size))#/10.0)*10.0
                randAppleY = round(random.randrange(0, display_height-block_size))#/10.0)*10.0
                snakeLength += 1

            elif lead_y + block_size > randAppleY and lead_y + block_size < randAppleY + AppleThickness:

                randAppleX = round(random.randrange(0, display_width-block_size))#/10.0)*10.0
                randAppleY = round(random.randrange(0, display_height-block_size))#/10.0)*10.0
                snakeLength += 1



        clock.tick(FPS)

    pygame.quit()
    quit()



gameLoop()

我得到的索引错误是这个代码

Traceback (most recent call last):
  File "C:\Users\BJBGaming\Desktop\FirstGame.py", line 165, in <module>
    gameLoop()
  File "C:\Users\BJBGaming\Desktop\FirstGame.py", line 132, in gameLoop
    snake(block_size, snakeList)
  File "C:\Users\BJBGaming\Desktop\FirstGame.py", line 35, in snake
    gameDisplay.blit(img,(snakelist[-1][0], snakelist[-1][1]))
IndexError: list index out of range

请帮帮我，我不知道怎么修。谢谢你

Answer 1

当然，错误在于访问snakelist[-1][0], snakelist[-1][1]。检查您的逻辑：

if len (snakeList) > snakeLength:
    del snakeList [0]

会是snakeLength == 0和len(snakeList) == 1的情况吗？如果是，则删除唯一的元素，导致snakeList为空