Combining duplicates into an array

Question

I have an array like below

[
{"st":"10:30,22:30","day":1},
{"st":"9:30,20:30","day":3},
{"st":"9:30,20:30","day":4},
{"st":"11:0,23:30","day":7},
{"st":"11:0,23:30","day":6},
{"st":"8:0,23:0","day":2},
{"st":"8:0,23:0","day":5}
]

I want to convert it like below

[
 {"st":"10:30,22:30","day":[1]},
 {"st":"9:30,20:30","day":[3,4]},
 {"st":"11:0,23:30","day":[7,6]},
 {"st":"8:0,23:0","day":[2,5]}
]

Based on the duplicate "st" values i want to merge those corresponding days. i was tried so many methods but i was unable to do. can anybody please help me out. Thanks in advance.

Can you give some examples of what you've tried?

gcampbell
– gcampbell

2016-07-05 07:42:58 +00:00
Commented Jul 5, 2016 at 7:42 — gcampbell
– gcampbell, Commented Jul 5, 2016 at 7:42

str · Accepted Answer · 2016-07-05 08:15:37Z

2

One approach is the following:

var yourArray = [
{"st":"10:30,22:30","day":1},
{"st":"9:30,20:30","day":3},
{"st":"9:30,20:30","day":4},
{"st":"11:0,23:30","day":7},
{"st":"11:0,23:30","day":6},
{"st":"8:0,23:0","day":2},
{"st":"8:0,23:0","day":5}
];

var newArray =
Array.from(new Set(yourArray.map(elem => elem.st))) // get unique st's
    .map(elem => ({
        st: elem,
        day: yourArray.filter(el => el.st === elem).map(el => el.day) // get array of days
}));

console.log(newArray);

Note that this uses ES6 features and you need to use a transpiler (e.g. Babel) to use it in non-ES6 compliant browsers.

Resources

edited Jul 5, 2016 at 8:15

answered Jul 5, 2016 at 8:01

str

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Comments

mtamma · Accepted Answer · 2016-07-05 08:25:09Z

1

This basic code might could help.

angular.module('MyApp', [])
  .controller('TestCtrl', function($scope) {
    $scope.originalArray = [{
      "st": "10:30,22:30",
      "day": 1
    }, {
      "st": "9:30,20:30",
      "day": 3
    }, {
      "st": "9:30,20:30",
      "day": 4
    }, {
      "st": "11:0,23:30",
      "day": 7
    }, {
      "st": "11:0,23:30",
      "day": 6
    }, {
      "st": "8:0,23:0",
      "day": 2
    }, {
      "st": "8:0,23:0",
      "day": 5
    }];
    $scope.result = [];

    (function() {
      angular.forEach($scope.originalArray, function(value) {
        var locateIndex = _.findIndex($scope.result, {
          'st': value.st
        });
        if (locateIndex === -1) {
          var currentDayValue = value.day;
          value.day = [currentDayValue];
          $scope.result.push(value);
          return;
        }

        $scope.result[locateIndex].day.push(value.day);
      });
    }).call()
  });

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.13.1/lodash.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="MyApp" ng-controller="TestCtrl">
  original array
  <div>{{ originalArray }}</div>
  <br/>result
  <div>{{ result }}</div>
</div>

PS: I use lodash as JS utility library. (findIndex helper function)

edited Jul 5, 2016 at 8:25

answered Jul 5, 2016 at 8:12

mtamma

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1 Comment

user2451830 Over a year ago

Perfectly working for my scenario. Thank you so much

Jack jdeoel · Accepted Answer · 2016-07-05 09:21:36Z

Create temp array for check duplicate st value by indexOf.Check st value exist in temp ,if not change your day value to array type .If exist push day to previous index and after deleted by splice

var object = [
{"st":"10:30,22:30","day":1},
{"st":"9:30,20:30","day":3},
{"st":"9:30,20:30","day":4},
{"st":"11:0,23:30","day":7},
{"st":"11:0,23:30","day":6},
{"st":"8:0,23:0","day":2},
{"st":"8:0,23:0","day":5}
];
var temp = [];
for(var i = object.length-1;i > 0;i--){
     if(temp.indexOf(object[i].st) != -1){
          var exist = temp.indexOf(object[i].st);
          object[exist].day.push(object[i].day);
          object.splice(i,1);
     }
     else{
         temp[i] = object[i].st;
         var d = object[i].day;
         object[i].day = [];
         object[i].day.push(d);
     }
}
console.log(object);

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