JES，嵌套的 if 语句无法正常工作

Question

我一直遇到由嵌套的 If then 语句无法正常工作而导致的运行时错误。对JES不是很有经验，所以为什么我要寻求帮助。基本上，（见下面的源代码）我的newX（用于w.函数randrange来生成新的xy坐标）和newY如果超过599或更低，则将该var设置回0。好吧，我看到了

getPixel（picture，x，y）：y （= -22） 小于 0 或大于高度 （= 599） 错误值为： 不适当的参数值（类型正确）。 尝试将参数传递给函数时出错。 请检查 E：\dOX\HW\INF 120\e_Project5.py 的第 39 行

from random import *
def main( ):
   #draw
   pic = makeEmptyPicture(600, 600, white)
   show(pic)
#for the 4 boxes 
boxCount = 0
#while statement to draw
while boxCount < 4:
   addRectFilled(pic, randrange(0,576), randrange(0,576), 25, 25, red)
   addArcFilled(pic, randrange(0,576), randrange(0,576), 10, 10, 0, 360, blue)
   boxCount = boxCount + 1
repaint(pic)
newX = 0
newY = 0
oldX = 0
oldY = 0
robotcount = 0
finished = 0 
safe = 0 
triggered = 0
while robotcount < 750 or finished != 1 or safe != 1 or triggered != 1:
   oldX = newX
   oldY = newY
   newX = newX + randrange(-25, 26)
   newY = newY + randrange(-25, 26)
   if newX > 599 or newX < 0:
      newX = 0
   elif newY > 599 or newY < 0:
      newY = 0
   px = getPixel(pic, newX, newY)
   color = getColor(px)
   if color == red:
   triggered = 1
      printNow("trig")
   elif color == blue:
      safe = 1
      printNow("safe")
   elif robotcount == 750:
      finished = 1
      printNow("Fin")
   addLine(pic, oldX, oldY, newX, newY, black)
   robotcount = robotcount + 1

Answer 1

我怀疑问题来自**elif** newY > 599 or newY < 0:这意味着如果触发了之前的测试（newX > 599 or newX < 0），则不会测试newY。将elif替换为if，它应该可以工作。