Netlogo添加到列表列表 [英] Netlogo adding to list of lists

问题描述

我希望将补丁变量值添加到空列表中.这些补丁被划分为不同的区域，我正在尝试查看某些补丁变量如何随区域而变化. 我有一个空列表列表(实际上包含12个列表，但是为了简单起见):

I am looking to add patch variable values to a list of empty lists. The patches are divided into different zones, and I'm trying to see how certain patch variables differ by zone. I have an empty list of lists (actually contains 12 lists, but for simplicity):

set mylist [[] [] [] []]

以及对应于不同区域的列表:

And a list corresponding to the different zones:

set zone-list [1 2 3 4]

这是我尝试建立列表的方式:

Here's how I'm trying to build the lists:

(foreach mylist zone-list [set ?1 lput (sum-zone-variable ?2) ?1])

to-report sum-zone-variable [ n ]
  report (sum [patch-variable] of patches with [zone = n])
end

运行此命令时，我的列表保持空白(即不变).我认为问题出在foreach语句上，但我不知道它是什么.有帮助吗?

When I run this, mylist stays empty (ie unchanged). I think the problem is with the foreach statement, but I can't figure out what it is. Any help?

推荐答案

我可以看到foreach mylist [ set ?1 ... ]背后的想法，但是NetLogo不能那样工作. set ?1 ...对原始列表无效. NetLogo列表是不可变的，?1不是对列表中可更新位置的引用-只是一个将值复制到其中的临时变量.所以set ?1 ...是您基本上不会写的东西.

I can see the thinking behind foreach mylist [ set ?1 ... ], but NetLogo doesn't work that way. set ?1 ... has no effect on the original list. NetLogo lists are immutable, and ?1 is not a reference to an updatable location in a list — it's just a temporary variable into which a value has been copied. So set ?1 ... is something you will basically never write.

如果我正确理解了您的问题，则此处的相关原语是map.这应该可以完成工作:

If I understand your question correctly, the relevant primitive here is map. This should do the job:

set mylist (map [lput (sum-zone-variable ?2) ?1] mylist zonelist)

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