Array Prototypes: insert(index,value) & remove(index)

November 19th, 2009 Marvin Blase

I've been searching the net for a couple of minutes but didn't find a working prototype in AS3 / 2 which fit my requirements. There were lots of prototypes but I wanted to remove an Array-key by just passing it's index. And I needed the other way around: inserting new keys to where-ever I want. Seemed like I'm the only man on earth ever needed this as none of the prototypes I found do so.

Example:

PLAIN TEXT

Actionscript:

1. // remove
2. var arr:Array = new Array("a", "b", "c", "d");
3. arr = arr.remove(1); // pass the index, not value!
4. trace(arr); // a, c, d
5.  
6. // insert
7. var arr:Array = new Array("a", "c", "d");
8. arr = arr.insert(1, "b");
9. trace(arr); // a, b, c, d

So I roughly made up my mind how to split, pop/shift and concat the Arrays to achieve the wanted. Didn't take too long and for sure I'd like to share it with you.

Array.remove(index:int):

PLAIN TEXT

Actionscript:

1. Array.prototype.remove = function(index:int):Array {
2.     var original:Array = this.slice(); // a, b, c, d
3.     var temp:Array = original.splice(index); // b, c, d
4.     temp.shift(); // c, d
5.     original = original.concat(temp); // a, c, d
6.     return original;
7. };

Array.insert(index:int, value:*):

PLAIN TEXT

Actionscript:

1. Array.prototype.insert = function(index:int, value:*):Array {
2.     var original:Array = this.slice(); // a, c, d
3.     var temp:Array = original.splice(index); // c, d
4.     original[index] = value; // b
5.     original = original.concat(temp); // a, b, c, d
6.     return original;
7. };

Posted in Codesnippets 13,503 views

10 Responses to “Array Prototypes: insert(index,value) & remove(index)”

1. Andrew says:

   22/10/2010 at 1:23 AM

   Brilliant, exactly what I was looking for, and I managed to convert it to AS2.
2. chapter 6 says:

   10/12/2010 at 10:26 AM

   Thanks for that awesome posting. It saved MUCH time :-)
3. ChessMax says:

   03/01/2011 at 11:50 PM

   try this (shorter and no array duplicated in the memory):

   Array.prototype.remove = function(index:int):Array
   {
   this.splice(index, 1);
   return this;
   };

   Array.prototype.insert = function(index:int, value:*):Array
   {
   this.splice(index, 0, value);
   return this;
   };
4. Marvin Blase says:

   10/01/2011 at 1:35 PM

   Right, thanks! Will check that out.
5. Visit Teton Valley says:

   14/01/2011 at 9:55 PM

   Any update on this ? Excellent information keep it up!
6. Chris Merry says:

   18/01/2011 at 12:51 PM

   ChessMax, that's a beautiful thing. Thank you.
7. Chris Merry says:

   18/01/2011 at 4:01 PM

   An extension of ChessMax's work, this prototype allows you to either move an element around inside an array or insert at the specified position

   Array.prototype.move = function(index:int, value:*):Array
   {

   var index_of:uint = this.indexOf(value)

   this.splice(index_of, 1);

   this.splice(index, 0, value);
   return this;

   };
8. Jeff says:

   18/01/2011 at 4:11 PM

   Great comments, thank you all!
9. Chris Merry says:

   29/01/2011 at 8:11 PM

   I found that using prototypes like this can interfere with the smooth running of a Tweener stack, which I've got around by using them as ordinary functions:

   function remove_from_a1(a1,index):void{

   a1.splice(index,1);

   trace(a1);

   }

   function insert_into_a1(a1,index,value:*):void{

   a1.splice(index,0,value);
   trace(a1);

   }

   function move_within_a1(a1,index,value):void{

   var index_of:uint = a1.indexOf(value)

   a1.splice(index_of, 1);

   a1.splice(index, 0, value);

   trace(a1);

   }
10. Scollan701@gmail.com says:

    05/04/2012 at 6:01 AM

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