Flex 3 Actionscript Array Subtract function

Can anyone tell me how to compare two array开发者_如何转开发s and delete the common terms in ActionScript?

Eg:

Array1 = [2,4,6,8,10,12]

Array2 = [1,2,3,4,5,6,7,8,9,10,11]

Array1 - Array2 = [12]

---

If you use ActionLinq, it is very easy to do set mathematics like this:

var array1:Array = [2,4,6,8,10,12];
var array2:Array = [1,2,3,4,5,6,7,8,9,10,11];

var subtraction:Array = Enumerable.from(array1)
                        .except(Enumerable.from(array2))
                        .toArray();

---

You can filter using a custom function. This is not an optimized way of filtering a difference of arrays, but it'll get the job done.

subtraction = Array1.filter(function(item:*, index:int, arr:Array){
  var i:int;
  var l:int;
  l = Array2.length;
  for ( i=0; i < l; i++ )
  {
    if ( Array2[i] == item )
    {
      return false;
    }
  }
  return true;
});

---

If you wish to knock out all duplicates from an Array then I suggest that you use a Set to make the lookup speed as fast as possible:

const a : Array = [ 2, 3, 4 ];
const b : Array = [ 3, 4, 5 ];

// Create a Set for Array 'b' to provide a fast lookup table.
const setB : Object = {};

var prop : *;
for each (prop in b) { 
    setB[key] = true 
};

// Find all values which only belong in Array 'a'.
const uniqueToA : Array = [];
for each (prop in a) {
    if (setB[prop] === undefined) {
        uniqueToA.push(prop);
    }
}

If you find yourself doing a lot of work with collections then I would advise you invest in a Collections Framework such as AS3Commons Collections.