How to get only unique items in a multidimensional array with JavaScript/jquery?

Question

I got for example a multidimensional array items with 2 dimensions. I get this array from a database, but it will fill up to 2600+ objects, but if i could some how unique this it would be around 30 objects. How to solve this?

The set up is: How i get the information:

$.getJSON(url1,function(data1)
{
    for (var i in data1.layers){
        $.each(data1.layers[i].legend, function( a, b ) {
            for(var a in data1.layers[i].legend[a]){
                $.each(data1.layers[i].legend, function( key, val ){
                    items.push({label: val.label, url: "long link" + val.url});
                });
            };
        });     
    };

items[0].label  
items[0].url 
items[1].label    
items[1].url

etc...

I found another stackoverflow page about this in php, but i can't get it to work in JavaScript/JQuery. Stackoverflow php solution

That looks like an array of objects, actually. You need to show where the data is coming from and how you're building the array. — JJJ, Dec 03 '13 at 15:29
Which parts will be unique? are all 2600 labels and urls similar, or is there just 30 different urls with lots of labels? — vogomatix, Dec 03 '13 at 15:33
@ Juhana i added the information of the items arrays. @vogomatix It will get ~30 different labels and urls, but it will "clone" them in the array. — Mike-N88, Dec 03 '13 at 15:33

score 0 · Answer 1 · answered Dec 03 '13 at 15:35

0

You're making a mistake in pushing them onto an array in the first place. You should be creating an associative array, with the key field the unique aspect.

answered Dec 03 '13 at 15:35

vogomatix

4,856
2
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score 0 · Accepted Answer · answered Dec 03 '13 at 15:36

Use a dictionary to see which item you have already:

var dict = {};

$.getJSON(url1,addToLocalArray);

function addToLocalArray(data1){

  for (var i in data1.layers){

    $.each(data1.layers[i].legend, function( a, b ) {

        for(var a in data1.layers[i].legend[a]){

            $.each(data1.layers[i].legend, function( key, val ){

              if(!dict[val.url+'-'+val.label]){
                // or create some sort of unique hash for each element...
                dict[val.url+'-'+val.label] = 1;

                items.push({label: val.label, url: "long link" + val.url});
              }

            });

        }
    });
  }
}

This does what i wanted thanks, tho i have to admit if i could change things at the server side i would do it. — Mike-N88, Dec 03 '13 at 15:48

score 0 · Answer 3 · answered Dec 03 '13 at 15:39

0

I would suggest either:

A)Push the Uniqueness filtering logic off to the database. It's much more efficient at this, and won't require exhaustive iteration.

B)Have a key for each unique Item (As vogomatix suggested).

answered Dec 03 '13 at 15:39

Fydo

1,396
16
29

If you can touch the server side I agree with this solution. – MarcoL Dec 03 '13 at 15:40

How to get only unique items in a multidimensional array with JavaScript/jquery?

3 Answers3

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