Question

我有这个代码，其中海龟在遇到墙壁和关闭的大门时会改变方向。

一开始没关系，但接下来会发出这条消息。

OF expected input to be a turtle agentset or patch agentset or turtle or patch but got NOBODY instead.
error while turtle 259 running OF
  called by procedure GO
  called by Button 'Go'

我可以发送整个模型。

 if state = 1 [fd speed
       ifelse [pcolor] of patch-at-heading-and-distance 0 1 = black or [pcolor] of patch-at-heading-and-distance 0 1 = red
       [ lt random-float 90]
       [fd 1]  
  ; ifelse [pcolor] of patch-ahead 1 = blue
  ;    [ lt random-float 360 ]   ;; We see a blue patch in front of us. Turn a random amount.
   ;   [ fd 1 ]

        if (pxcor >= 89 and pxcor <= 90) and (pycor > 5 and pycor < 10) [facexy (87 + random 3) 25 fd speed]
        ;if (pxcor >= -10 and pxcor <= 1) and (pycor >= 6 and pycor <= 23 ) [facexy ( 7 + random 3) (26 + random 3) fd speed]
        if (pxcor >= 85 and pxcor <= 90) and (pycor = 26) [
          let choice random 2
          fd speed
          if choice = 1 [leftbench]
          if choice = 0 [facexy (87 + random 3) 76]
        ]
        if (pxcor >= 83 and pxcor <= 92) and (pycor >= 75 and pycor <= 77) [rightbench fd speed]
        if pcolor = brown and not any? other turtles-here
        [ move-to patch-here
          set seated? true
          set pcolor orange
          ]
      ]

Answer 1

你的模型是否在一个或两个方向关闭了世界边缘？

如果是这样，那么你的代码必须处理有时这个补丁的可能性：

patch-at-heading-and-distance 0 1

如果乌龟靠近世界边缘，

将不存在。如果发生这种情况，那么patch-at-heading-at-distance将返回nobody，当您尝试执行时：

[pcolor] of patch-at-heading-and-distance 0 1 = black

您收到错误，因为无法从不存在的补丁中检索到pcolor。

解决此问题的典型方法是执行以下操作：

let target patch-at-heading-and-distance 0 1
if is-patch? target and ...

最后，我想知道你是否真的是patch-at-heading-and-distance 0 1。它相当于patch-at 0 1，它指的是乌龟以北的补丁;不知道你为什么要那样。如果你想在乌龟之前测试补丁（如果乌龟使用fd将会登陆的补丁），请使用patch-ahead。

NetLogo：避免墙壁和关闭的门错误

1 个答案: