如何在我的代码中修复“IndexError：列表索引超出范围”？

Question

我对 Python 很陌生，我想测试一个瓷砖地图系统。 当我尝试加载图块时，我收到错误消息IndexError: list index out of range 。 为了解决这个问题，我需要做些什么，以及其他人将来喜欢它？ 确切的错误：

Traceback (most recent call last):
  File "N:/Python/Projects/Projects/First Topdown/First Topdown.py", line 114, in <module>
    pygame.draw.rect(screen, colors[tilemap[row][column]], (column*tilesize, row*tilesize, tilesize, tilesize))
IndexError: list index out of range

我听说这意味着我正在尝试访问一个none或空的值。 这是关于tilemap的代码部分。 没有最后一个绘图位，rest 工作正常。 （这不是很多其他代码，只是运动。）

import pygame

pygame.init()

tilesize = 64
mapwidth = 16
mapheight = 13
screen = pygame.display.set_mode((mapwidth*tilesize, mapheight*tilesize))


pygame.display.set_caption("Aspen")

WALLTOP = 0
WALLBOT = 1
GRASS = 2
wallTop = (128, 128, 128)
wallBot = (210, 105, 30,)
grass =   (50, 205, 50)

colors = {
WALLTOP : wallTop,
WALLBOT: wallBot,
GRASS : grass
}

tilemap = [
            [WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP,
            WALLTOP, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, GRASS, WALLTOP,
            WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP]
]


running = True
while running:

    screen.fill((64, 64, 64))

    for row in range(mapheight):
        for column in range(mapwidth):
            pygame.draw.rect(screen, colors[tilemap[row][column]], (column*tilesize, row*tilesize, tilesize, tilesize))

    pygame.display.update()

Answer 1

您收到IndexError是因为您只在tilemap中定义了一行，但是由于以下语句，外部for循环提供了从0到mapheight-1的row索引：

for row in range(mapheight):

为避免该错误，请尝试将其更改为：

for row in range(len(tilemap)):

更新

我想我已经弄清楚你想要做什么了。 正如我之前所说， IndexError是因为tilemap中的行数与您尝试使用嵌套for循环显示的行数不匹配。

下面我已经修复了tilemap的定义方式，因此它具有适当数量的行和列（并且还简化了一些其他定义，并向显示循环添加了一些事件处理，以允许脚本正常关闭而不是在无限循环）。

import pygame

pygame.init()

tilesize = 64
mapwidth, mapheight = 16, 13

screen = pygame.display.set_mode((mapwidth*tilesize, mapheight*tilesize))

pygame.display.set_caption("Aspen")

WALLTOP, WALLBOT, GRASS = range(3)

wallTop = (128, 128, 128)
wallBot = (210, 105, 30,)
grass =   (50, 205, 50)

colors = {
    WALLTOP : wallTop,
    WALLBOT : wallBot,
    GRASS   : grass
}

tilemap = [
    [WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP],
    [WALLTOP, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLBOT, WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   GRASS,   WALLTOP],
    [WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP, WALLTOP],
]

running = True
while running:

    screen.fill((64, 64, 64))

    for row in range(mapheight):
        for column in range(mapwidth):
            pygame.draw.rect(screen, colors[tilemap[row][column]], (column*tilesize, row*tilesize, tilesize, tilesize))

    # Process user-events.
    for event in pygame.event.get():
        if event.type == pygame.QUIT:  # User clicked to close window.
            running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE: # Press escape key to quit.
                running = False

    pygame.display.update()

Answer 2

好的，我终于明白你在做什么了。

即使您的 tilemap 是一维的，您也尝试对您的 tilemap 进行第二个切片。 对于多维 arrays，最好使用 numpy arrays imo。 当您在我的代码中打印出 tmap 时，您会明白我的意思，它更具可读性。 此外，由于 python 与缩进一起使用，因此通过将不同的 arguments 分隔为单独的行来组织长 function 调用是一个好主意。 否则，您的代码中会出现非常难以阅读的长行。

import pygame
import numpy as np

pygame.init()

# Define base values for tiles
tsize, width, height = 64,16,13

# Set the stage with an empty 2D array full of zeroes
# Create the tilemap dynamically from width and height.
tmap = np.zeros((height,width),dtype=int)

# defines the screen I guess?
screen = pygame.display.set_mode((width*tsize, height*tsize))
pygame.display.set_caption("Asspain")

# You can now change the tilemap manually.
# You have three unique rows, so you can
# just make lists of those and later insert
# them into your np.array
r1 = [1]*width

r2 = [1]
r2.extend([2]*14)
r2.extend([1])

r3 = [1]
r3.extend([0]*14)
r3.extend([1])

# turn your lists into np.arrays so they work
# with your tmap.
r1, r2, r3 = np.array(r1),np.array(r2),np.array(r3)

# insert the rows at the appropreate positions
# mind you, indexing works a bit different in
# np.arrays than in python builtin lists.
tmap[0] = r1.copy()
tmap[1] = r2.copy()
tmap[2:12] = r3.copy()
tmap[12] = r1.copy()

# You now have a nice and readable tmap.
# You can make the map creation process
# as manual as you want, I just used shortcuts
# based on symmetry.
print(tmap)

# Now you can just iterate over every element
# via double iteration, or using indices.
# I've heard iterating over indices using range
# is always faster.

# define colormap
cmap = {0:(50, 205, 50),
        1:(128, 128, 128),
        2:(210, 105, 30,)}

# this is unneccessary, but it's good to know
# that numpy arrays also have a len() like
# attribute called shape.
width, heigth = tmap.shape[0], tmap.shape[1]

# Gameloop
while True:

    # Is this the default color of a tile?
    # Do you need that?
    screen.fill((64, 64, 64))

    for row in range(width):
        for col in range(heigth):
            pygame.draw.rect(screen, 
                             cmap[tmap[row][col]],
                             (col*tsize,
                              row*tsize,
                              tsize,
                              tsize))
    pygame.display.update()

编辑：我注意到你做了很多字典切片，非常慢。 如果您不需要在游戏循环中重复切片字典（即 map 不会更改），请不要。 我已经编写了一些额外的代码，它会生成与上面相同的tmap数组作为图块的模板，但是这一次，我还要转换一个数组，它将颜色三元组映射到这些位置。

通过这种方式，您可以使用快速 numpy arrays 一次创建整个 map，它利用阵列的 dtype 类型转换，同时仍受益于先前指定的可读性。

import numpy as np
import matplotlib.pyplot as plt

tsize, width, height = 64,16,13
tmap = np.zeros((height,width),dtype=int)
cmap = np.zeros((height,width,4),dtype=int)

r1 = [1]*width

r2 = [1]
r2.extend([2]*14)
r2.extend([1])

r3 = [1]
r3.extend([0]*14)
r3.extend([1])

r1, r2, r3 = np.array(r1),np.array(r2),np.array(r3)

tmap[0] = r1.copy()
tmap[1] = r2.copy()
tmap[2:12] = r3.copy()
tmap[12] = r1.copy()

cdct = {0:np.array((50, 205, 50, 200),dtype=int),
        1:np.array((128, 128, 128, 200),dtype=int),
        2:np.array((210, 105, 30, 200),dtype=int)}

for posy, row in enumerate(tmap):
    for posx, col in enumerate(row):
        cmap[posy,posx] = cdct[col].copy()

fig, ax = plt.subplots()
plt.axis('off')

ax.imshow(cmap)

As you can see, matplotlib can easily visualise X,Y,Z arrays, which the imshow() function can read as a bitmap. X 是行，Y 是列，Z 是颜色三元组。 实际上，我将 Z 设为四个元素，以便用第四个元素切换透明度。 这样，您可以创建一次 bitmap 作为背景，然后直接在颜色四元组上进行迭代，而无需在 while 循环的每次迭代中执行 16*13 慢速字典切片。 显然，绘图只是它外观的视觉演示，并且是一个漂亮的小工具，用于为您的游戏 map 建模。

而且因为它使用了类型转换的 numpy arrays 并且避免了很多缓慢的操作，因此与以前相比应该快如闪电。