AS3: How to convert a Vector to an Array

Question

What's the nicest way to convert a Vector to an Array in Actionscript3?

The normal casting syntax doesn't work:

var myVector:Vector.<Foo> = new Vector();
var myArray:Array = Array(myVector); // calls the top-level function Array()

due to the existance of the Array function. The above results in an array, but it's an array with a single element consisting of the original Vector.

Which leaves the slightly more verbose:

var myArray:Array = new Array();
for each (var elem:Foo in myVector) {
    myArray.push(elem);
}

which is fine, I guess, though a bit wordy. Is this the canonical way to do it, or is there a toArray() function hiding somewhere in the standard library?

Answer 1

There is a function called forEach which both Vector and Array has which you can use. Basically it calls a function for each element in the vector. This is how it works:

var myVector:Vector.<Foo> = new Vector();
var myArray:Array = [];

myVector.forEach(arrayConverter);

function arrayConverter(element:*, index:int, array:Array):void{
    myArray[myArray.length] = element;
}

But I couldn't find a function which just moves all the values from the Vector to an Array. Another solution could be that you create a class which extends the Vector class and then you have a public function called toArray() and then you have that code in that function so you don't have to write it each time you want to convert.

Vector documentation

Answer 2

your approach is the fastest ... if you think it's to verbose, then build a utility function ... :)

Answer 3

a function call for each element in the Vector would be a LOT slower, particularly in a longer Vector. however, these examples are probably all equivalent, unless you're dealing with a fairly long Vector/Array -- legibility and ease of use are generally more important than optimization.

that said, i think the fastest way is to use a while loop with an iterator compared against 0.

var myArray:Array = new Array(myVector.length);
var i:int=myVector.length;
while (i--) {
    myArray[i] = myVector[i];
}

unfortunately, you can't stuff this technique into a method for ease of repeated use, because there's no way to specify a Vector method parameter of a generic base type.... :(

Answer 4

If you have a vector of strings, you could do:

myArray = myVec.join(",").split(",");

for a quick and dirty Array conversion.

Good luck ~ Tyler