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A note on jQuery .unique()

under HTML

I was dealing with an array full of years (2009, 2009, 2010, 2010, 2009, 2010), and I wanted to easily remove duplicate entries in the array.

I found that jQuery had a .unique() function that removes duplicates. However, there if the duplicates are not in a sequential order, it will miss some of the items in the array.

var yearArray = new Array(2009, 2009, 2010, 2010, 2009, 2010);
$.unique(yearArray);

This returns 2009, 2010, 2009, 2010. The function missed a couple of the duplicates. This is simply fixed by sorting the array and then passing it into the unique function.

var yearArray = new Array(2009, 2009, 2010, 2010, 2009, 2010);
yearArray.sort();
$.unique(yearArray);

This should then return 2010, 2009. Hope this helps. :)

!! UPDATE !!
I hate Internet Explorer. I just discovered that the .unique() function works with DOM objects and because IE sucks, it doesn’t work properly. So, I had to replace the .unique() with the following code:

var yearArray = new Array(2009, 2009, 2010, 2010, 2009, 2010);
// still sort the array
yearArray.sort();

//$.unique(yearArray);

yearArray = uniqueArray(yearArray);


function uniqueArray(a){
    temp = new Array();
    for(var i = 0; i < a.length; i ++){
        if(!contains(temp, a[i])){
            temp.length+=1;
            temp[temp.length-1] = a[i];
        }
    }
    return temp;
}
function contains(a, e){
    for(j=0;j<a.length;j++)if(a[j]==e)return true;
    return false;
}

More code, but it works in all browsers now.

Thanks to Developer Snippets for the code

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  1. Kyle Henderson Said,

    Thanks so much for this tip! Was banging my head against the wall with this one!

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