Question

55

Copy an associative array in JavaScript

rated 0 times [ 61] [ 6] / answers: 1 / hits: 17052 / 12 Years ago, sun, april 22, 2012, 12:00:00

I've the following piece of code for copying one associative array to other,

<script>



    var some_db = new Array();



    some_db["One"] = "1";



    some_db["Two"] = "2";



    some_db["Three"] = "3";



    var copy_db = new Array();



    alert(some_db["One"]);



    copy_db = some_db.slice();



    alert(copy_db["One"]);



</script>

But the second alert says "undefined".. Am I doing something wrong here? Any pointers please...

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jimmieo

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answered 12 Years ago tyriquehenryq · Accepted Answer

In JavaScript, associative arrays are called objects.

<script>

    var some_db = {

       "One" : "1",

       "Two" : "2",

       "Three" : "3"

    };



    var copy_db = clone(some_db);



    alert(some_db["One"]);



    alert(copy_db["One"]);



    function clone(obj) {

        if (null == obj || "object" != typeof obj) return obj;

        var copy = obj.constructor();

        for (var attr in obj) {

            if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);

        }

        return copy;

    }

</script>

I would normally use var copy_db = $.extend({}, some_db); if I was using jQuery.

Fiddle Proof: http://jsfiddle.net/RNF5T/

Thanks @maja.