group by array of array

Question

I have an array, which is currently grouped like this:

{
  data: [ListingModel, ListingModel, ListingModel, ListingModel, ListingModel, ListingModel]
};

I'd like it to be grouped like this:

{
  groupedData: [
    [ListingModel, ListingModel],
    [ListingModel, ListingModel],
    [ListingModel, ListingModel]
  ]
};

So you mean to pair them up? Have you tried anything for yourself yet? Please include that — musefan, Sep 11 '15 at 09:38
If lodash will do then check out the [chunk](https://lodash.com/docs#chunk) function — Gruff Bunny, Sep 11 '15 at 09:39
Chunk in underscorejs answered here [http://stackoverflow.com/questions/8566667/split-javascript-array-in-chunks-using-underscore-js](http://stackoverflow.com/questions/8566667/split-javascript-array-in-chunks-using-underscore-js) — Nico Vignola, Sep 11 '15 at 09:46

musefan · Accepted Answer · 2015-09-11T09:44:56.057

Just loop the input 2 at a time, and create a new array for each pair. This new array then gets added to an overall result array...

var groupedData = [];

for(var i = 0; i < data.length; i+=2){
    groupedData.push([data[i], data[i+1]]);
}

You may want to add validation in the event you have an odd number of elements.

Here is a working example, I just used strings in this example for the ListingModel as you don't define that in your question.

Hardeep Singh · Answer 2 · 2015-09-11T09:47:46.803

1

var group_data = [];

for (var i = 0; i < data.length; i+=2)
{
    var arr = [];
    arr.push(data[i]);
    if ( (i + 1) < data.length)
    {
        arr.push(data[i + 1]);
    }

    group_data.push(arr); //push to main array
}

edited Sep 11 '15 at 09:47

answered Sep 11 '15 at 09:42

Hardeep Singh

743
1
8
18

Could you ask your friends to also upvote my answer please, much appreciated :) – musefan Sep 11 '15 at 09:56

Sherali Turdiyev · Answer 3 · 2015-09-11T11:34:16.587

0

If i understand your question, try this.

var data = [1, 2, 3, 4, 5];
    var result = [];
    for (var i = 0, len = data.length / 2; i < len; i++) {
      var two = [];
      
        if (data[2 * i]) {
            two.push(data[2 * i])
        }
        if (data[2 * i+1]) {
            two.push(data[2 * i+1])
        }
      result.push(two);
    }
    console.log(result);//output: [[1, 2], [3, 4], [5]]

edited Sep 11 '15 at 11:34

answered Sep 11 '15 at 10:15

Sherali Turdiyev

1,745
16
29

Don't reference other answers. In this case it kind of makes yours redundant as you are acknowledging that there is already an answer very similar to yours, so why bother posting your answer at all – musefan Sep 11 '15 at 11:11
Thanks for advice, @musefan. I didn't copy others answer. I tried to find optimum way(faster way). – Sherali Turdiyev Sep 11 '15 at 11:37

score 0 · Answer 4 · answered Sep 11 '15 at 10:17

u see to change associative array from single array

var data=['ListingModel', 'ListingModel2', 'ListingModel3',   'ListingModel4',' ListingModel5', 'ListingModel6'];
var new_arr = new Array();
for(var i in data){        
if(i < 3){      
    new_arr[i] = [data[i*2],data[i*2+1]];            
}
}
console.log(new_arr);

group by array of array

4 Answers4