Retrieving a specific element in my javascript array

Question

I have the following javascript array:

var vat = [
{ id: '', description: '' },
{ id: 'Zero', description: '0%' },
{ id: 'Six', description: '6%' },
{ id: 'Nineteen', description: '19%' },
{ id: 'TwentyOne', description: '21%' }];

I need to get the description of the element with id of 'Six'. I think it is possible but I did not succeed.

Any help is welcome.

Thanks.

Similar questions: http://stackoverflow.com/q/16339635/218196, http://stackoverflow.com/q/12553274/218196. — Felix Kling, Jun 12 '13 at 13:20

score 5 · Accepted Answer · answered Jun 12 '13 at 13:15

5

You could filter the array to leave only the item you are looking for:

var desc = vat.filter(function (item) {
    return item.id === "Six";
})[0].description;

Note that Array.prototype.filter is an ES5 method and is not supported by older browsers. You can find a polyfill for it in the MDN article linked to previously.

answered Jun 12 '13 at 13:15

James Allardice

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This is of course a valid solution, but I might suggest that if possible, turning 'vat' into an object instead of an array using the ids as the property names. – Tyler Biscoe Jun 12 '13 at 13:17

score 0 · Answer 2 · answered Jun 12 '13 at 13:16

0

If you know that it is the third item then:

vat[2]['description']

otherwise you could use filter as suggested by James Allardice

answered Jun 12 '13 at 13:16

Andy G

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It's an array of object, so the description is accessed by . not [] – David Ansermot Jun 12 '13 at 13:18
@mArm.ch, using brackets is perfectly valid. Look up javascript bracket notation. – Tyler Biscoe Jun 12 '13 at 13:19
It would be necessary as well, if the key (the attribute) contained spaces. – Andy G Jun 12 '13 at 13:25

score 0 · Answer 3 · answered Jun 12 '13 at 13:16

The structure of your array makes this a bit more complicated than necessary. Here's an alternative structure for which it's much simpler:

var vat = { '': '', 'Zero': '0%' } // and so on
vat['Zero'] // gives '0%'

In case you're stuck with the structure you've got, you'll need a loop. For example:

var result;
for (var i = 0; i < vat.length; i++) {
  if (vat[i].id == 'Six') {
    result = vat[i].description;
    break;
  }
}

PS. the filter method suggested in a different answer makes this easier, but it requires a browser that supports at least JavaScript 1.6.

score 0 · Answer 4 · answered Jun 12 '13 at 13:16

If you want to directly access it, you have to know the position.
Example :

var myDesc = vat[2].description;

Or you can loop on it.
Example :

var myDesc = null
for (i in vat) {
    if (vat[i].id == 'Six')  {
        myDesc = vat[i].desc;
    }
}

Hope it's what you needed.

score 0 · Answer 5 · answered Jun 12 '13 at 13:18

0

    for(var i=0;i < vat.length;i++){
        if(vat[i].id == "Six"){
            alert(vat[i].description);
        }
    }

answered Jun 12 '13 at 13:18

user23031988

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10

Could you explain your answer please? – Ben Jun 12 '13 at 13:38
I added a piece of code that extracts in the `vat[i].description` the `description` of the element with `id` of 'Six'. – user23031988 Jun 12 '13 at 15:00

Retrieving a specific element in my javascript array

5 Answers5