how to group by the array values dynamically in javascript

Question

hi all i am using javascript i have a set of array i need to group by the object

code

 var data = [{BuildingID: "5", FloorId: "65", one: 12, two: 15,three: 12},
            {BuildingID: "5", FloorId: "65", one: 12, two: 15,three: 12},
            {BuildingID: "6", FloorId: "65", one: 12, two: 15,three: 12},
            {BuildingID: "6", FloorId: "65", one: 12, two: 15,three: 12}]

i am trying to do group by the BuildingID add one,two,three NOTE:one two three is not static

Excepted Output

  var data = [{BuildingID: "5", FloorId: "65", one: 24, two: 30,three: 24},
              {BuildingID: "6", FloorId: "65", one: 24, two: 30,three: 24} ]

possible duplicate https://stackoverflow.com/questions/14446511/what-is-the-most-efficient-method-to-groupby-on-a-javascript-array-of-objects — Agam Banga, Jun 06 '17 at 12:37

Nina Scholz · Accepted Answer · 2017-06-06T12:51:29.553

You could use a dynamic approach by using a hash table and an array for the static keys of the object.

var data = [{ BuildingID: "5", FloorId: "65", one: 12, two: 15, three: 12 }, { BuildingID: "5", FloorId: "65", one: 12, two: 15, three: 12 }, { BuildingID: "6", FloorId: "65", one: 12, two: 15, three: 12 }, { BuildingID: "6", FloorId: "65", one: 12, two: 15, three: 12 }],
    staticKeys = ['BuildingID', 'FloorId'] ,
    grouped = data.reduce(function (hash) {
        return function (r, a) {
            var key = a[staticKeys[0]];
            if (!hash[key]) {
                hash[key] = {};
                staticKeys.forEach(function (k) {
                    hash[key][k] = a[k];
                });
                r.push(hash[key]);
            }
            Object.keys(a).forEach(function (k) {
                if (staticKeys.indexOf(k) === -1) {
                    hash[key][k] = (hash[key][k] || 0) + a[k];
                }
            });
            return r;
        };
    }(Object.create(null)), []);

console.log(grouped);

.as-console-wrapper { max-height: 100% !important; top: 0; }

it contains the keys for the static values. as hash key, it uses then value of the object with the key of index zero. — Nina Scholz, Jun 06 '17 at 12:59
Now it's working add two more fields in group by means what should i fo @Nina var key = a[staticKeys[0,1]];? — jose, Jun 06 '17 at 13:05

score 1 · Answer 2 · answered Jun 06 '17 at 13:14

here is a snippet code that work for me,

it assums you know the key attribute of the object

var arr = [ { id: 1, name: 'bob' }, { id: 1, name: 'bill' }, { id: 1, name: 'bill' } ]

var noDuplicate = [];
var unique = {};

$.each(arr, function(key, item) {

    if (! unique[item.id + "-" + item.name]) {
        noDuplicate.push(item);
        unique[item.id + "-" + item.name] = true;
    }
});

console.log(noDuplicate);

hope it helps ;)

regards.

try to make a fiddle @fxlacroix – jose Jun 06 '17 at 13:31 — jose, Jun 06 '17 at 13:31

score 1 · Answer 3 · answered Jun 09 '17 at 09:22

You can try this snippet, the "ouput" variable contains the result;

var data = [{ BuildingID: "5", FloorId: "65", one: 12, two: 15, three: 12 }, { BuildingID: "5", FloorId: "65", one: 12, two: 15, three: 12 }, { BuildingID: "6", FloorId: "65", one: 12, two: 15, three: 12 }, { BuildingID: "6", FloorId: "65", one: 12, two: 15, three: 12 }]
var groupBy = function(input, key) {
   return input.reduce(function(list, x) {
     list[x[key]] = x;
     return list;
   }, {});
};
var grouped = groupBy(data, 'BuildingID'), output=[];
for ( var key in grouped ) { output[output.length] = grouped[key]; }
console.log(output);

how to group by the array values dynamically in javascript

code

Excepted Output

3 Answers3

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