Select subset of objects from javascript object array

Question

I've got a long array of objects:

var myObj = {
  a: "aaa",
  b: "bbb",
  c: "ccc",
  d: "ddd",
  ...
}

I'd like to create a new object array that consists of every object except the first two:

var myObj2 = {
  c: "ccc",
  d: "ddd",
  ...
}

Obviously myObj.slice(2) doesn't work (as much as I'd like it to), and I can't select them all by name (myObj.c, myObj.d, etc) because there are more than 100 objects, and potentially more to be added.

What's the best way to select a range of objects in a object array?

There's no such thing as the "first two" properties. The order of properties in a object is not guaranteed. — Robby Cornelissen
– Robby Cornelissen, Commented Feb 23, 2016 at 5:06
I see just one object here, not an array. There is no such thing as an "object array", although you could have an array of objects. slice isn't working because slice is an array method, not an object method. — jmargolisvt
– jmargolisvt, Commented Feb 23, 2016 at 5:09
Also mention the formula. It is not necessary to be a KEY name..It could be value as well.. — Rayon
– Rayon, Commented Feb 23, 2016 at 5:09
Are your keys necessarily "a", "b", etc.? Or something that could be sorted alphabetically? — jmargolisvt
– jmargolisvt, Commented Feb 23, 2016 at 5:17

jmargolisvt · Accepted Answer · 2016-02-23 06:11:44Z

2

You may want to recompose this, but here is a general approach.

First, here's your object with some sortable keys:

var obj = {B201: "apple", B342: "orange", B123: "pear"}

Then create an array of the first two keys after sorting:

var arr = Object.keys(obj).sort().slice(0,2);

This returns ["B123", "B201"].

Define a function that removes the object property based on the key name:

function remove (e, i, a) {delete obj[e];};

Then call that function for each property:

arr.forEach(remove);

You should get the object with the "first two" properties removed:

Object {B342: "orange"}

answered Feb 23, 2016 at 6:11

jmargolisvt

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Comments

Taj Ahmed · Accepted Answer · 2016-02-23 05:27:52Z

2

You can use below method to remove the keys you don't want

var myObj = {a: "aaa",b: "bbb",c: "ccc",d: "ddd"}

function filterObject(obj,filterObject){
    var newObj = {}
    for(key in obj){
        if(!filterObject[key]){
            newObj[key] = obj[key];
        }
    }
    return newObj;
}

console.log(filterObject(myObj,{a:true,b:true}))

Sample Output:

{ c: 'ccc', d: 'ddd' }

answered Feb 23, 2016 at 5:27

Taj Ahmed

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Comments

Prakash Rao · Accepted Answer · 2016-02-23 05:18:08Z

Suppose you have an array of objects like this

myObj = [
                {
                  a: "aaa",
                  b: "bbb",
                  c: "ccc",
                  d: "ddd",
                  ...
                },

                {
                  a: "aaa",
                  b: "bbb",
                  c: "ccc",
                  d: "ddd",
                  ...
                },

                {
                  a: "aaa",
                  b: "bbb",
                  c: "ccc",
                  d: "ddd",
                  ...
                },

                {
                  a: "aaa",
                  b: "bbb",
                  c: "ccc",
                  d: "ddd",
                  ...
                },
            ];

Now run a loop for main array

Inside that loop through each object inside array. Increment a counter in each turn and check it is greater than 2 then insert it in main array myObj again

$.each(myObj, function( index, value ) {
    var counter = 0;
    $.each(value, function( index2, value2 ) {
        counter++;
        if(counter > 2){
            myObj[] = value;
        }
    });

});

if you have different structure for the main array of object then slight change will be there

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