Remove Duplicate Elements from an Array using jQuery

A very useful jQuery function is the $.unique() that removes all duplicate elements from an array of DOM elements. However this function only works on arrays of DOM elements, not strings or numbers. Thanks to an anonymous reader for pointing this out in the comments section. Here's an updated code on how to remove duplicate elements from an array of integers. 

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Remove duplicate elements from array (from DevCurry.com)</title>
    <script type="text/javascript"
    src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.min.js">
    </script>
    <script type="text/javascript">
        $(function () {
            var arr = [1, 2, 3, 2, 6, 4, 3, 7];
            $("#orig").html("Original array :" + arr.join(","));
            arr = $.unique(arr);
            $("#uniq").html("Unique array :" + arr.sort().join(","));
        });
    </script>
</head>

<script type="text/javascript">
    $(function () {
        var arr = [1, 2, 3, 2, 6, 4, 3, 7];
        $("#orig").html("Original array :" + arr.join(","));
        arr = arr.unique();
        $("#uniq").html("Unique array :" + arr.sort().join(","));
    });

    // Original function by Alien51
    Array.prototype.unique = function () {
        var arrVal = this;
        var uniqueArr = [];
        for (var i = arrVal.length; i--; ) {
            var val = arrVal[i];
            if ($.inArray(val, uniqueArr) === -1) {
                uniqueArr.unshift(val);
            }
        }
        return uniqueArr;
    }

</script>
</head>
<body>
    <div>     
        <p id="orig"></p>
        <p id="uniq"></p>
    </div>
</body>
</html>

The Array.prototype extends the definition of the array by adding properties and methods. Here we have created a custom function called unique which removes duplicates from an array.

Note: In case of a string array, the search is case-sensitive. So the function does not consider “Put” and “put” as duplicate

OUTPUT

image

See a Live Demo

6 comments:

  1. AnonymousAugust 31, 2010 at 2:30 AM

    It doesn't work dude... as the API states:

    'Remove all duplicate elements from an array of elements. Note that this only works on arrays of DOM elements, not strings or numbers.'

    ReplyDelete
  2. AnonymousDecember 8, 2010 at 3:30 AM

    Dude...U serious, this only works on DOM elements (sad but true) not TEXT or NUMBERS.

    //Limp

    ReplyDelete
  3. AnonymousDecember 13, 2010 at 6:52 PM

    dude i tried your demo it doesn't work at all

    ReplyDelete
  4. Suprotim AgarwalDecember 13, 2010 at 9:12 PM

    Sorry guys! The code and the demo have been updated. Please check it again.

    ReplyDelete
  5. AnonymousJanuary 7, 2011 at 8:28 PM

    Thanks! It seems like the function by Alien51 should really be included in jQuery.

    ReplyDelete
  6. Suprotim AgarwalJanuary 7, 2011 at 8:32 PM

    I second that! It's a nice piece of code. Btw, do you know who's Alien51? A google search doesn't help here.

    I want to thank him for this piece of code which I found online.

    ReplyDelete