var a:Array = ["a", "b","c","z","E","g"]; var b:Array = ["a", "e","Z"]; trace(returnUnique(a,b)) function returnUnique(a:Array,b:Array):Array{ var arr:Array = []; for each(var i:Object in a) { if (b.indexOf(i) == -1) { arr.push(i); } } return arr; }