Remove value from associative array

Question

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Remove specific element from a javascript array?

I am having an array, from which I want to remove a value.

Consider this as an array

[ 'utils': [ 'util1', 'util2' ] ]

Now I just want to remove util2. How can I do that, I tried using delete but it didn't work.

Can anyone help me?

The surrounding square brace should be a bracket if this is an object literal. — David G, Jan 27 '13 at 15:24
var object = { 'utils': [ 'util1', 'util2' ] } object.utils.splice(1, 1); — Ali NajafZadeh, Aug 03 '21 at 16:58

David G · Accepted Answer · 2013-01-27T15:45:04.413

13

Use the splice method:

var object = { 'utils': [ 'util1', 'util2' ] }

object.utils.splice(1, 1);

If you don't know the actual position of the array element, you'd need to iterate over the array and splice the element from there. Try the following method:

for (var i = object.utils.length; i--;) {
    var index = object.utils.indexOf('util2');

    if (index === -1) break;

    if (i === index) {
        object.utils.splice(i, 1); break;
    }
}

Update: techfoobar's answer seems to be more idiomatic than mine. Consider using his instead.

edited Jan 27 '13 at 15:45

answered Jan 27 '13 at 15:25

David G

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+1, you're nearly there: It's `object.utils.splice(1, 1)`. You have to tell it how many to remove (the second `1`). The first `1` just tells it at what index to do something. *Edit:* Yup, there you go. :-) – T.J. Crowder Jan 27 '13 at 15:26
What if the object was defined like this: `var object = { 'utils': [ 'util2', 'util1' ] }`? – Darin Dimitrov Jan 27 '13 at 15:27
1

Darin wanted to say, what if the order of the elements is different. It's all answered in the question this one is a duplicate of. – Felix Kling Jan 27 '13 at 15:28
Yes, that's what I meant. This solution will only work in some very particular case. – Darin Dimitrov Jan 27 '13 at 15:29
@DarinDimitrov Then you would do `.utils.splice(0)` – David G Jan 27 '13 at 15:29
What if you don't know the order? What I mean is that the usefulness of your solution is pretty limited. You assume way too many things about the order of elements in the array. – Darin Dimitrov Jan 27 '13 at 15:29
@DarinDimitrov Good question. I think you'd have to loop. – David G Jan 27 '13 at 15:29
Sure, could you update your answer to include this information and provide more useful solution? – Darin Dimitrov Jan 27 '13 at 15:30
@David - You do not need to loop through the utils array, and then do a `Array.indexOf()` inside it. – techfoobar Jan 27 '13 at 15:47
@techfoobar what is your alternative suggestion in this case? – David G Jan 27 '13 at 15:49
@David - Unless there are multiple items in the array with the same value (that you need deleted), you can just do an `indexOf()` once and splice from the index it returns. – techfoobar Jan 27 '13 at 15:50

score 5 · Answer 2 · answered Jan 27 '13 at 15:38

5

You can use Array.splice() in combo with Array.indexOf() to get the desired behavior without having to loop through the array:

var toDelete = object.utils.indexOf('util1');
if(toDelete != -1) {
    object.utils.splice(toDelete, 1);
}

answered Jan 27 '13 at 15:38

techfoobar

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score 0 · Answer 3 · edited Jan 27 '13 at 15:31

I think there is no such thing called associative array in Javascript. It is actually an object.

[ 'utils': [ 'util1', 'util2' ] ]

For this line, I don't think it would compile. You should write this instead.

var obj = { 'utils': [ 'util1', 'util2' ] }

So to remove the element "util2" in the array (the inside array), there are 2 ways.

use pop()

obj["utils"].pop(); // obj["utils"] is used to access the "property" of the object, not an element in associative array

reduce the length
```
obj["utils"].length --;
```

Remove value from associative array

3 Answers3