Removing duplicates in an Array, why this code is not working

Question

Hi I have written below code

function unique(th){
   var obj = {};
   for(var i = 0, n = th.length; i < n ; i++){
       obj[th[i]] = th[i];
   }    
   obj.length = n ;
   return Array.prototype.slice.call(obj);
}

But, this is giving me unwanted output. Please help me to correct this. here is the fiddle.

Why downvote..? I have written unwanted output. Not unwanted and something.... — Exception, Jun 29 '12 at 12:04
@Adnan Shammout Hmm ok, but thanks :-) Even downvotes helped this time... — Exception, Jun 29 '12 at 12:10
possible duplicate of [Unique values in an array](http://stackoverflow.com/questions/1960473/unique-values-in-an-array) — Qantas 94 Heavy, Mar 05 '14 at 05:57

Denys Séguret · Accepted Answer · 2012-06-29T12:00:01.733

1

I don't know what was your logic so I build a slightly different and working function, trying to make it as clear as possible :

function unique(th){
   var yetseen = {};
   var newarray = [];
   for(var i = 0, n = th.length;  i < n ; i++){
       var val = th[i];
       if (!yetseen[val]) {
           yetseen[val] = true;
           newarray.push(val);
       }
   }    
   return newarray;
}

edited Jun 29 '12 at 12:00

answered Jun 29 '12 at 11:54

Denys Séguret

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Brandon Boone · Answer 2 · 2012-06-30T13:12:50.230

0

Use Underscore.js

It's a library with a host of functions for manipulating arrays.

_.uniq

_.uniq(array, [isSorted], [iterator]) Alias: unique Produces a duplicate-free version of the array, using === to test object equality. If you know in advance that the array is sorted, passing true for isSorted will run a much faster algorithm. If you want to compute unique items based on a transformation, pass an iterator function.

Example

alert(_.uniq([2,2,1,4,5,6,2,9,1,1,6,3,2,1,9,6,4], false)); //yields 2,1,4,5,6,9,3

edited Jun 30 '12 at 13:12

answered Jun 29 '12 at 12:13

Brandon Boone

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Thanks for referring underscore.js – Exception Jun 29 '12 at 12:14
1

@SoI - Just discovered it a month or so ago. Been loving it ever since! – Brandon Boone Jun 29 '12 at 12:15

Removing duplicates in an Array, why this code is not working

2 Answers2

Use Underscore.js

_.uniq

Example