Get last children of a node?

Questions & Answers
1

I have the following hierarchy:

gameObject 1
gameObject A
	gameObject i
		gameObject k
gameObject B
	gameObject ii
gameObject C

And I want to store an array with the last nodes of the hierarchy that are not root, say in this example my array will have this objects

gameObject k
gameObject ii
gameObject C

Any suggestions?

2

The standard terminology is to call those nodes “leaves”.

Sounds like you need a recursive function that traverses the tree of game objects, adding leaves to the array. Something like the following, but I have not compiled or tested this:

function FindLeaves(var parent : Transform, var leafArray : Array)
{
   if (transform.childCount == 0)
   {
      leafArray.Add(parent);
   }
   else
   {
       for (var child : Transform in transform)
       {
          FindLeaves(child, leafArray);
       }
   }
}

You would call this function by passing in the root gameObject and an empty array.

Note: when debugging recursive functions if you make a mistake and get an infinite loop you can lock up Unity, unless you are running the scripts in a source level debugger like Mono or Visual Studio. So save your work before pressing Play. :slight_smile:

4

You could use a recursive function like the one below to traverse the object hierarchy, identify each last child and add it to the List:

import System.Collections.Generic;

static var lastChildren = new List.< Transform>;

static function GetLastChildren(trf: Transform){
  if (trf.parent && trf.childCount == 0){ // if this is a last child...
    lastChildren.Add(trf); // add it to the array
  } else { // but if not a last child...
    // verify all of its children (if any):
    for (var child: Transform in trf.transform){
      GetLastChildren(child);
    }
  }
}

To get the last children of some object, pass its transform to this function:

  GetLastChidren(someObject.transform);

NOTE: I have little experience with List, thus there may exist some stupid error in the code!

3

private ArrayList _sons;

void hasChildren(Transform t)
{
	int i = 0;
	foreach (Transform child in t)
	{
		hasChildren(child);
		i++;
	}
	
	if (i == 0)
	{
		_sons.Add(t);
	}
}