Deleting a row from javascript object

Question

I have a javascript object which looks like this :-

var myObject = [{"id": "1", "URL": "http://shsudhf.com", "value": "1"}, 

                {"id": "2", "URL": "http://shsusadhf.com", "value": "2"},

                {"id": "3", "URL": "http://shsudsdff.com", "value": "0"}];

Now , I have to delete all the rows in the object with id value 2. How can this be done ?

I was using plain javascript. Recreating will be a bit slow if the number of rows are very large, I guess. Yes, it will be mutually used — Prashant Singh
– Prashant Singh, Commented Dec 12, 2012 at 6:56
Do you need the original array after you remove the items with the id of "2"? — Ian
– Ian, Commented Dec 12, 2012 at 7:02

Ian · Accepted Answer · 2012-12-12 07:12:31Z

5

If you don't need the original array after "deleting" rows, you can use splice like this:

http://jsfiddle.net/rmcu5/1/

var myArray = [{"id": "1", "URL": "http://shsudhf.com", "value": "1"},
                {"id": "2", "URL": "http://shsusadhf.com", "value": "2"},
                {"id": "3", "URL": "http://shsudsdff.com", "value": "0"}];

function removeItemsById(arr, id) {
    var i = arr.length;
    if (i) {   // (not 0)
        while (--i) {
            var cur = arr[i];
            if (cur.id == id) {
                arr.splice(i, 1);
            }
        }
    }
}

removeItemsById(myArray, "2");

console.log(JSON.stringify(myArray));

It doesn't create a new array, just modifies the original in place. If you need the original array and all of its items, then use one of the other solutions that return you a modified copy of the original.

edited Dec 12, 2012 at 7:12

answered Dec 12, 2012 at 7:06

Ian

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6 Comments

Ray Toal Over a year ago

+1 for splice as this is the "native" way to remove items from an array.

Prashant Singh Over a year ago

Can you explain a bit about arr.splice ?

Ian Over a year ago

@PrashantSingh It takes 3 parameters (only the first 2 we're worried about). The first parameter is the index to start removing items from, and the second parameter is how many items to remove. I just set it as 1 because we only want to remove the single item in the loop (its id is 2)

Ian Over a year ago

@PrashantSingh The looping starts at the end of the array and loops to the beginning, which is important for something like this because you're modifying the array directly while looping through it and can throw off the looping

Ian Over a year ago

@PrashantSingh No problem. Just remember, this modifies the original array. If you want to keep the original array in its state but also get a copy that has specific items removed, you would need to use someone else's solution. It really depends on what you specifically need to do

|

elclanrs · Accepted Answer · 2012-12-12 07:04:20Z

5

Note that what you call myObject is actually an array therefore you can use array methods on it:

myObject = myObject.filter(function( obj ) {
  return obj.id != 2;
});

Demo: http://jsfiddle.net/elclanrs/LXpYj/

edited Dec 12, 2012 at 7:04

answered Dec 12, 2012 at 6:58

elclanrs

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4 Comments

Ray Toal Over a year ago

That's very nice but the OP did ask for a mutator. I don't agree with the OP's request for a mutator. Your solution is obviously the best, since removing from the middle of an array is awful. If the OP agrees that this is okay, I'll +1.

Ian Over a year ago

@PrashantSingh Note that this is not available on IE < 9. You'd have to include a polyfill just for the filter method to work on them

Prashant Singh Over a year ago

@Ian Ok, that means I can't use this :O

elclanrs Over a year ago

Yes but you need to add a polyfill for older browsers. A polyfill is just some code that adds that functionality if is not present. There's a 140bytes filter polyfill here: gist.github.com/1031656. Even with the polyfill the code will be shorter and more readable than most other ways of doing this.

Zaheer Ahmed · Accepted Answer · 2012-12-12 07:08:36Z

2

try this:

function deleteObject(array,id)
{
 var newObject=[]; 
  for (var o in array) {
       if(array[o].id!=id)
          newObject.push(array[o]);
    }
return newObject;
}

working JS fiddle

You can do without creating new array, you need to write remove function:

Array.prototype.remove = function() {
    var what, a = arguments, L = a.length, ax;
    while (L && this.length) {
        what = a[--L];
        while ((ax = this.indexOf(what)) !== -1) {
            this.splice(ax, 1);
        }
    }
    return this;
};

Without New Array Delete Object

edited Dec 12, 2012 at 7:08

answered Dec 12, 2012 at 6:55

Zaheer Ahmed

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1 Comment

Prashant Singh Over a year ago

Is recreating the array is the only solution ?

silly · Accepted Answer · 2012-12-12 07:15:40Z

0

try it with filter (its an array not a object)

var rr = [{"id": "1", "URL": "http://shsudhf.com", "value": "1"},  {"id": "2", "URL": "http://shsusadhf.com", "value": "2"}, {"id": "3", "URL": "http://shsudsdff.com", "value": "0"}];


rr = rr.filter(function(e) {
    return e.id != 2;
});

answered Dec 12, 2012 at 7:15

silly

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Comments

Muqito · Accepted Answer · 2012-12-12 07:00:28Z

-1

Here you go, this is without recreating the array or anything.

 var myObject = [{"id": "1", "URL": "http://shsudhf.com", "value": "1"}, 

                {"id": "2", "URL": "http://shsusadhf.com", "value": "2"},

    {"id": "3", "URL": "http://shsudsdff.com", "value": "0"}];

for(i=0,iMax=myObject.length;i<iMax;i++){
    (function (a) { 
        if(this.id=="2"){
          delete myObject[a];
        }
    }).call(myObject[i],i);
}

console.log(myObject);

jsFiddle

http://jsfiddle.net/gG2zz/1/

answered Dec 12, 2012 at 7:00

Muqito

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3 Comments

adeneo Over a year ago

You do realize that THIS would do exactly the same, and it still would'nt remove anyting, it just sets the array items to undefined ?

Muqito Over a year ago

@adeneo well I'm sorry if it's late and I'm tired. but why do you say it doesn't delete it link

adeneo Over a year ago

delete works fine on objects, like in the linked question, but on arrays the index is not updated, and the length would still be the same, so it's not really "deleted", that's the main problem with arrays, deleting stuff is a pain in the a$$, and usually takes some slicing and dicing.

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