AS2 push to array outside of clip does nothing - arrays

Question

was wondering if someone could show me what I'm doing wrong here.
I have some old AS2 flash code I'm trying to get working.
First I create a few arrays in frame 1 of the main timeline like so-
var typeArr:Array = new Array();
for (var i:Number = 1; i < 5; i++)
{
_root.typeArr[i] = "data goes here";
}
Then I have a movieclip dynamically attached on the main stage that when clicked appends one of the arrays we created by pushing the string 'foo' to it-
stop();
_root.myType=3;//this can be any of our array numbers
this.onPress=function(){
var foo:String="test";
_root.typeArr[_root.myType].push(foo);
trace(_root.typeArr[_root.myType]);
}
Where _root.typeArr[_root.myType] is the array name and number _root.typeArr3, but pushing the data does not work and returns nothing.
However, if I test it directly using-
_root.typeArr[_root.myType]=foo;
It will store the data once (_root.typeArr3=test), so I can't see why it won't push to that array as multiple elements each time like- "test,test,test"
It's driving me crazy.
Thanks! :)

Answer 1

_root.typeArr[_root.myType] is equal to "data goes here" so you are pushing string to a string, which doesn't work.
If you would like to append the new string, you should do something like:
_root.typeArr[_root.myType]+=foo;
and you will get: data goes heretest
If you have different data structure instead of "data goes here" the key may lie in the format of this data.

Answer 2

var typeArr:Array = new Array();
// 'i' must start from 0 because the first element is typeArr[0]
for (var i:Number = 0; i < 5; i++)
{
typeArr[i] = i;
// trace(typeArr[i]); // 0,1,2,3,4
}
// trace(typeArr); // 0,1,2,3,4
myType = 3;
bt.onPress = function()
{
var foo:String = "test";
// push method puts the element at the end of your array
// typeArr.push(foo);
// trace(typeArr); // 0,1,2,3,4,test
// splice method replace the 4e element (index 3) of your array
typeArr.splice(myType, 1, foo);
trace(typeArr); // 0,1,2,test,4
}