AS3 Fastest way to merge multiple arrays - arrays

Question

I'm trying to write a function where I can specify any amount of array, and the return value will be an array containing the contents of all of the specified arrays.
I've done this, but it seems like a really slow and ugly way of doing it:
var ar1:Array = [1,2,3,4,5,6,7,8,9];
var ar2:Array = ['a','b','c','d','e','f','g','h'];
function merge(...multi):Array
{
var out:String = "";
for each(var i:Array in multi)
{
out += i.join(',');
}
return out.split(',');
}
trace(merge(ar1, ar2));
Is there an inbuilt and more efficient / nice way of achieving this? The result does not need to be in the same order as the input - completely unsorted is fine.

Answer 1

You can use concat.
If the parameters specify an array, the elements of that array are concatenated.
var ar1:Array = [1,2,3,4,5,6,7,8,9];
var ar2:Array = ['a','b','c','d','e','f','g','h'];
var ar3:Array = ['i','j','k','l'];
var ar4 = ar1.concat(ar2, ar3); // or: ar1.concat(ar2).concat(ar3);
To make a single array out of a 2 dimensional array you can use this function:
private function flatten(arrays:Array):Array {
var result:Array = [];
for(var i:int=0;i<arrays.length;i++){
result = result.concat(arrays[i]);
}
return result;
}
// call
var ar4 = [ar1, ar2, ar3];
var ar5 = flatten(ar4);
You can also use varargs to merge multiple arrays:
private function merge(...arrays):Array {
var result:Array = [];
for(var i:int=0;i<arrays.length;i++){
result = result.concat(arrays[i]);
}
return result;
}
// call
var ar5 = merge(ar1, ar2, ar3);

Answer 2

I don't know if this method is faster than using loops, but it is a (fancy) quick way to merge 2 arrays. (and it works in Javascript and Actionscript)
var arr1:Array = [1,2,3,4,5]
var arr2:Array = [6,7,8,9,10]
arr1.push.apply(this, arr2); // merge
// arr1.push.call(this, arr2); // don't use this. see comment below
trace(arr1) // 1,2,3,4,5,6,7,8,9,10

Answer 3

function merge(...multi):Array
{
var res:Array = [];
for each(var i:Array in multi)
{
res = res.concat(i);
}
return res;
}
Didnt try it, but something like this would help you.