In actionscript 3 how to remove duplicates from array

By on April 21, 2010 in Mixed

actionscriptToday I was working in  actionscript 3 + php project. I was working in an array and I needed to remove duplicate entries from array. In php its very easy to remove duplicate entries.

There is a function in php named array_unique($array); that removes duplicate elements from array. So in php I could easily use

    $arr = array('a', 'b', 'a', 'c', 'd', 'b');
    $arr = array_unique($arr); //removes duplicate entries

But there is no such type of built in function in actionscript 3 for array. So I created my own function and used it

function removeDuplicate(arr:Array) : void{
    var i:int;
    var j: int;
    for (i = 0; i < arr.length - 1; i++){
        for (j = i + 1; j < arr.length; j++){
            if (arr[i] === arr[j]){
                arr.splice(j, 1);
            }
        }
    }
}

Now just call the function and pass an array

var arr:Array = new Array("a", "b", "a", "c", "d", "b");
removeDuplicate(arr);

splice(startIndex:int, deleteCount:uint); method removes elements from an array. So using 2 simple loops I solved my problem. But as my arrays are short 20 elements max so I don’t need to optimize this function.

reference: http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/Array.html

About mahmud ahsan

I am a Bangladeshi computer programmer and mobile apps entrepreneur. I develop iPhone applications, games and I am a founder of iThinkdiff.net. My previous work experience was web application development and I am a ZCE. I blog at Thinkdiff.net. Beside my profession currently I am studying Masters of Information Science & Technology (Major is Data Mining in health information technology) by research in Multimedia University Malaysia. More about me
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3 Responses to In actionscript 3 how to remove duplicates from array

  1. Sam Tyson May 10, 2011 at 9:40 pm #

    I believe the 2nd loop needs to sequence from the end to i+1. The problem is that the item at j is removed, then j is incremented – skipping a record

    try
    05: for (j = arr.length – 1; j > i; j–) {

    Reply
  2. AS3 script July 29, 2011 at 7:38 pm #

    I need like this… but I m doing something wrong in this :- please check once and let me know solution if you know….

    var mainArr:Array = ["cat","dog","chocolate","fire","food","house","market","butter",
    "fruit","ham","computer","door","hen"]
    // c,d,f,m,b,h = 6
    removeDuplicate(mainArr);

    function removeDuplicate(arr:Array) : void{
    var i:int;
    var j: int;
    for (i = 0; i < arr.length; i++){
    for (j = i + 1; j < arr.length; j++){
    if (arr[i].substr(0,1) == arr[j].substr(0,1)){
    arr.splice(j,1);
    }
    }
    }
    trace(arr)
    trace(arr.length)
    }

    Reply
  3. okp December 22, 2011 at 4:10 pm #

    A much more elegant solution:

    arr.filter(function(e:*, i:int, a:Array):Boolean {return a.indexOf(e) == i;});

    source: http://www.razorberry.com/blog/archives/2008/09/03/as3-removing-duplicates-from-an-array/

    Reply

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