Comments on: Find all unique values from array or collection

By: harishvardhan

harishvardhan — Thu, 21 Oct 2010 12:37:22 +0000

i have a arraycollection in which each element is a dictionary
for ex: Item 1: Fontstyle:Italic
1:46 item 2:Fontstyle :bold
item3:Underline :true
in this array collection i want to remove the fontstyle attributed items and add it to a new dictionary where in it contains only the unique values

how to do this?

can you email me please?harishvardhan@ymail.com

By: Brian Bishop

Brian Bishop — Tue, 15 Jun 2010 09:59:49 +0000

Nice post. Heres a helpful addition to the function that I needed. If you have an array of objects (any type of objects), you can pass in which property of the objects you wish to target.

/** * Get the unique values stored within an arrayCollection * * @param The arrayCollection to search * @param The property value of the arrayCollection's objects to target * @return an arrayCollection of unique items; */ public function getUniqueValues (collection:ArrayCollection, propertyName:String):ArrayCollection {


			var length:Number = collection.length;

			var dict:Dictionary = new Dictionary();
			//this should be whatever type of object you have inside your AC

			var obj:Object;

			for(var i:int = 0; i < length; i++){

				obj = collection.getItemAt(i);
				dict[obj[propertyName]] = obj[propertyName];

			}

//this bit goes through the dictionary and puts data into a new AC var unique:ArrayCollection = new ArrayCollection(); for(var propertyString:String in dict){ unique.addItem(dict[propertyString]); } return unique; }

By: Kenneth

Kenneth — Tue, 23 Feb 2010 23:39:32 +0000

As long as you remember the following when using the keys then it works fine and is much quicker than a double loop.
The Dictionary class lets you create a dynamic collection of properties, which uses strict equality (===) for key comparison. When an object is used as a key, the object’s identity is used to look up the object, and not the value returned from calling toString() on it. Primitive (built-in) objects, like Numbers, in a Dictionary collection behave in the same manner as they do when they are the property of a regular object.

By: Bendy

Bendy — Tue, 23 Feb 2010 08:32:43 +0000

I do believe the dictionary hash uses AS3′s built-in “equality”: comparing by reference. You only get unique objects by reference.

If you want unique objects by equality, you should use ObjectUtil.compare and a double loop, checking each item against the unique items found so far. This is something like O(n^2).

By: Suma Gowda

Suma Gowda — Fri, 29 Jan 2010 22:42:33 +0000

Thank You

By: VANESSA

VANESSA — Fri, 22 Jan 2010 13:38:52 +0000

thanks for this code. It will definitely be useful innumberable times for me…
Good job and keep blogging…

By: Chris Lyles

Chris Lyles — Thu, 07 May 2009 19:06:47 +0000

Thanks for taking the time to publish your handy work…it’s been very helpful.