trace(xGetUniqueArray(array1).sort());  // 出力: a,b,c,d
function xGetUniqueArray(_array:Array):Array {
	var result_array:Array = new Array();
	var oValues:Object = new Object();
	var nLength:Number = _array.length;
	for (var i:Number = 0; i<nLength; ++i) {
		var myValue:Object = _array[i];
		if (!oValues[myValue]) {
			oValues[myValue] = true;
			result_array.push(myValue);
		}
	}
	return result_array;
}