printcount如何导致列表索引超出范围错误？

问题描述

我只是在鬼混，决定对高斯分布进行可视化处理，并且以某种方式出现了该错误。我以前从未见过此错误，而最奇怪的部分是，每次循环运行时它都不会发生。这是完全随机的。有时它在循环的第一次迭代中出错，有时它根本不出错。 print()函数在传递int时如何返回索引错误。这是所有代码：

import math
import pygame
import os

wS = 500

n = 50

os.environ["SDL_VIDEO_WINDOW_POS"] = "%d,%d" % (5,5)

pygame.init()

window = pygame.display.set_mode((wS,wS),0)
li = [math.floor(random.gauss(350,20)) for i in range(50)]
lmax = 0
lmin = 1000
off = wS/2

leng = len(li)

for i in range(len(li)):
    if li[i] > lmax:
        lmax = li[i]

xV = wS/n
xV2 = wS/lmax
print(li)

def run():
    global li
    global xV
    global lmax
    global off


    keys = pygame.key.get_pressed()
    count = 0
    p = pygame.PixelArray(window)
    while not keys[pygame.K_ESCAPE] and not keys[pygame.K_SPACE] and count < (leng - 1):
        print(count)
        event = pygame.event.get()
        keys = pygame.key.get_pressed()

        x = int(xV * count)

        y = int(off + ((li[count]/lmax) * off))

        p[x][y] = (255,255,255)
        count+=1
    print("done")
    pygame.display.update()
    keys = pygame.key.get_pressed()
    while not keys[pygame.K_ESCAPE] and not keys[pygame.K_SPACE]:
        event = pygame.event.get()
        keys = pygame.key.get_pressed()

run()

错误：

Traceback (most recent call last):
  File "*redacted*",line 58,in <module>
    run()
  File "*redacted*",line 41,in run
    print(count)
IndexError: array index out of range

解决方法

使用pygame.PixelArray时，os事件被阻止。 pygame.event.get()和pygame.key.get_pressed()都将在像素阵列表面被锁定时返回错误。

这是更新的代码。我从循环中删除了事件。我还添加了对x，y坐标的检查，以确保它们在数组中。

import math
import pygame
import os
import random

wS = 500

n = 50

os.environ["SDL_VIDEO_WINDOW_POS"] = "%d,%d" % (5,5)

pygame.init()

window = pygame.display.set_mode((wS,wS),0)

li = [math.floor(random.gauss(350,20)) for i in range(50)]
lmax = 0
lmin = 1000
off = wS/2

leng = len(li)

for i in range(len(li)):
    if li[i] > lmax:
        lmax = li[i]

xV = wS/n
xV2 = wS/lmax
print(li)

def run():
    global li,xV,lmax,off

    count = 0
    p = pygame.PixelArray(window)  # lock surface for drawing

    while count < (leng - 1):
        x = int(xV * count)
        y = int(off + ((li[count]/lmax) * off))
        if x < wS and y < wS: p[x,y] = (255,255,255)
        count+=1
        
    p.close()  # unlock surface
        
    print("done")
    pygame.display.update()
    keys = pygame.key.get_pressed()
    while not keys[pygame.K_ESCAPE] and not keys[pygame.K_SPACE]:
        event = pygame.event.get()
        keys = pygame.key.get_pressed()

run()

index-error pygame python