Regrouping javascript array

Question

I have the below javascript array with me

var test =[{
Maths:{
    ST1:10,
    ST2:2,
    ST3:15}
},
{
Science:{
    ST1:50,
    ST3:40}
    }
]

I want to generate the array shown below out of this

var t = [{ST1:{
               Maths:10,
               Science:50
              },
          ST2:{
               Maths:2,
               Science:0
              },
          ST3:{
               Maths:15,
               Science:40
              }
         }]

I tried using the code shown below

for (var key in test) {
  if (test.hasOwnProperty(key)) {
  for (var key1 in test[key]){
    //console.log(key1)}
    var abc = test[key][key1];
    for(var x in abc)
    {

    console.log(x+key1+abc[x])

    }

    }
  }
}

I am new to this help me doing this.

There's no JSON in your question. I think your use of that term is causing confusion. — user1106925
– user1106925, Commented Jun 7, 2012 at 18:52

score 1 · Accepted Answer · 2012-06-07 19:19:58Z

1

This does mostly what you want...

var t = {};
for (var i = 0; i < test.length; i++) {
    for (var name in test[i]) {
        for (var level in test[i][name]) {
            if (!t[level])
                t[level] = {}
            t[level][name] = test[i][name][level]
        }
    }
}

Only thing missing is to get the Science:0 for when a STx value is missing under a section.

DEMO: http://jsfiddle.net/eHwBC/

Result:

{
    "ST1": {
        "Maths": 10,
        "Science": 50
    },
    "ST2": {
        "Maths": 2
    },
    "ST3": {
        "Maths": 15,
        "Science": 40
    }
}

Keep in mind that there's no guaranteed order when using for-in for enumeration.

If the labels (Math, Science, etc) are known in advance, then you can ensure that each object gets all labels.

If not, a separate loop can be done. Depending on the approach, it could be done before or after this main loop.

edited Jun 7, 2012 at 19:19

answered Jun 7, 2012 at 19:07

user1106925

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1 Comment

user1106925 Over a year ago

Oops... You wanted it wrapped in an Array. Add t = [t] to the end.

smartcaveman · Accepted Answer · 2012-06-07 18:53:47Z

0

Do you know about `JSON.stringify(t)`?

It will convert an object literal to JSON.

Mozilla's documentation of this function is available at https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/JSON/stringify.

You can also read this blog article for further explanation

edited Jun 7, 2012 at 18:53

answered Jun 7, 2012 at 18:48

smartcaveman

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Comments

Selvakumar Arumugam · Accepted Answer · 2012-06-07 19:20:21Z

0

Try this:

var test =[{
Maths:{
    ST1:10,
    ST2:2,
    ST3:15
    }
},
{
Science:{
    ST1:50,
    ST3:40}
    }
];

var result = [];
for(i = 0; i <= test.length; i++){
  var resultRow = {};
  for(key in test[i]){
    for(subKey in test[i][key]){
      if(resultRow[subKey] == undefined){
        resultRow[subKey] = {};
      }
      resultRow[subKey][key] = test[i][key][subKey];
    }
  }
  result.push(resultRow);
}

edited Jun 7, 2012 at 19:20

Selvakumar Arumugam

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answered Jun 7, 2012 at 19:19

Wilson Freitas

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Comments

Selvakumar Arumugam · Accepted Answer · 2012-06-07 19:48:00Z

0

Try like below,

/* Iterator start */
var t = {};
for (var i = 0; i < test.length; i++) {  //Iterate Maths, Science,..   
    for (var key in test[i]) {           //Iterate Math
        for (var iKey in test[i][key]) { //Iterate ST1, ST2, ST3
          var s = (t.hasOwnProperty(iKey))?t[iKey]:createObject();                    
          s[key] = test[i][key][iKey];
          t[iKey] = s;
        }
    }
}
/* Iterator End */ 

p = [];
p.push(t);
//^- p is what you want

// Separate function so you can add more items later without changing logic
function createObject () {
    return {'Maths' : 0, 'Science': 0};
}

DEMO and Proof below,

enter image description here

edited Jun 7, 2012 at 19:48

answered Jun 7, 2012 at 19:09

Selvakumar Arumugam

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Do you know about `JSON.stringify(t)`?