Remove element with custom index from array Javascript

Question

I have a couple of arrays that looks a bit like these:

arr['a'] = 'val1';
arr['b'] = 'val2';
arr['c'] = 'val3';

The index is not an integer, it is a string. I want to remove arr['b'] from the array completely. I have tried:

arr.splice('b', 1);

It does not work, and it might be because the index in not an integer, according to w3schools this is the problem "index - Required. An integer".

A possible solution could be looping through all arrays and re-creating them with an integer index and then an array holding the custom indexes as values and the equivalent integer index as its index.

This seems like a tad unnecessary and a waste of resources, is there a smarter more effective and simpler solution?

Preferably an arr.splice that will work with a non-integer index.

I have looked through plenty of posts that covers how to remove elements from arrays by index and values, but none covers how to remove elements using a non-integer index.

Example posts that I have found: 0 1 2

Any and all help is greatly appreciated!

//Edit, used following as a solution.

function aObj() {
    this.a = ""; 
    this.b = [];
}

var aObjs = [];
aObjs.push(new aObj);
aObjs.push(new aObj);
aObjs.push(new aObj);

aObjs[0].a = "val1";

aObjs.splice(1, 1);

Looks a bit different than what I used in my first example, but this is more accurate towards how I used it. May not be the best way to do it, but it works.

Is there a reason you're using an array? Sounds like you should use an object instead — Nick White
– Nick White, Commented Aug 31, 2014 at 14:13
Well... There might be no other reason than me not knowing I could... I shall look into this. Thanks. — Daniel
– Daniel, Commented Aug 31, 2014 at 14:17

Mritunjay · Accepted Answer · 2014-08-31 14:14:26Z

2

Don't use array for string indexes, use objects like bellow

var arr = {} //create a object

arr['a'] = 'val1'; //asign values
arr['b'] = 'val2';
arr['c'] = 'val3';

console.log(arr) //prints {a: "val1", b: "val2", c: "val3"}

delete arr['a']  //delete a key

console.log(arr) // prints {b: "val2", c: "val3"}

answered Aug 31, 2014 at 14:14

Mritunjay

25.9k7 gold badges57 silver badges71 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Daniel Over a year ago

Used this as a start after reading undefined's and Nick White's answers, had to redo a lot of code, but was probably worth it. Updated question with solution.

showtime Over a year ago

delete arr['a'] ? Really? cmmon man dont post BS like this

Denis Shulepov · Accepted Answer · 2014-08-31 14:15:02Z

1

Well it does not work, because you are using an array as a dictionary, which it's not. First of all use object for that. Second use delete to remove a property:

var dict = { 'a': 'val1', 'b': 'val2', 'c': 'val3' };
delete dict.a;

answered Aug 31, 2014 at 14:15

Denis Shulepov

3811 silver badge6 bronze badges

Comments

KooiInc · Accepted Answer · 2014-09-01 06:20:52Z

As said before, this is not an Array. If it should be an array, it looks like this

var arr = ['val1', 'val2', 'val3'];

Now you can use Array.splice to remove value 'val2':

arr.splice(1,1);
// or
arr.splice(arr.indexOf('val2'),1);
// or even
arr = arr.filter(function (v){ return v !== 'val2'});

If it should be an object, its declariation looks like:

var obj = {a: 'val1', b: 'val2', c: 'val3'};

And if you want to delete 'val2' whilst not knowing the key for it you can loop:

for (var key in obj) {
  if (obj[key] === 'val2';
  delete obj[key];
}
// or (mis)use Object.keys 
Object.keys(obj)
      .filter(function(v){
               return this[v] === 'val2' ? !(delete this[v]) : true;
              }, obj);

Knowing this, you can create a helper method for Objects and Arrays:

function removeByValue(objOrArr, value) {
   if (objOrArr instanceof Array && objOrArr.length) {
     var found = objOrArr.indexOf(value);
     if (found) { objOrArr.splice(found,1); }
   }
   if (objOrArr instanceof Object) {
     var keys = Object.keys(objOrArr);
     if (keys.length) {
       keys.filter(function(v){
               return this[v] === value ? !(delete this[v]) : true;
              }, objOrArr);
     }
   }
   return objOrArr;
}
// usage (using previous arr/obj)
removeByValue(arr, 'val2'); // arr now ['val1','val3']
removeByValue(obj, 'val2'); // obj now {a:'val1', c: 'val3'}

Example

Collectives™ on Stack Overflow

Remove element with custom index from array Javascript

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related