Access object by name in array list

Question

I have an object that contains an array list of objects. I'd like to get the value of an object within the array list.

example

var data = { 
             items1: [{ id: 1, name: 'foo' }, { id: 2, name: 'bar' }], 
             items2: [{ id: 3, name: 'foo' }, { id: 4, name: 'bar' }] 
           };

I'm trying to access the name of id:1 in array list items1.

I thought it would be something like

data['items1']['id'].name

but I think I'm missing something. Anybody know what I might be doing wrong

For starters, that appears to be invalid json, given you don't have a comma after the first item. — Daedalus
– Daedalus, Commented Sep 22, 2013 at 6:00
Feel free to correct the issue you see, I just quickly modified the post from another example on the web to try and demonstrate what I'm trying to do. — Code Junkie
– Code Junkie, Commented Sep 22, 2013 at 6:02
Not going to. One never modifies the code in the OP's question, as that changes the meaning. If the code is faulty, or they misposted, it is their job to fix/correct it. — Daedalus
– Daedalus, Commented Sep 22, 2013 at 6:04

Chad · Accepted Answer · 2013-09-22 06:10:36Z

5

This is an object with 2 keys (items1 and items2), both of which are arrays. Within each array are elements which are objects, each containing 2 keys (id and name).

To get the id of the first element of the items1 array you would do:

data.items1[0].id

which would return 1.

If you wanted to search for the object with a name of 'bar' in items2 you could do something like:

function find(item, name) {
    //no such array
    if(!data[item])
        return;

    //search array for key
    var items = data[item];
    for(var i = 0; i < items.length; ++i) {
        //if the name is what we are looking for return it
        if(items[i].name === name)
            return items[i];
    }
}

var obj = find('items2', 'bar');
obj.id; //4
obj.name; //'bar'

I highly suggest reading about JavaScript Objects and Arrays.

edited Sep 22, 2013 at 6:10

answered Sep 22, 2013 at 6:04

Chad

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2 Comments

Code Junkie Over a year ago

In kelsadita's example, he shows me being able to use ['items1'], something I'm going to dynamically pass in, is that okay to do?

Chad Over a year ago

You may want to read up on javascript objects to learn how keys work. Doing data.items2 is just sugar for data['items2'], and something like var k = 'items2'; data[k]; is the same thing.

Jackson Ray Hamilton · Accepted Answer · 2013-09-22 06:16:12Z

3

You can only access array items by their numeric index. For example:

// The first item in the array
data['items1'][0].name
// The second
data['items1'][1].name

If you want to lookup by id, you can make a little function to do that for you:

function getItemById(anArray, id) {
    for (var i = 0; i < anArray.length; i += 1) {
        if (anArray[i].id === id) {
            return anArray[i];
        }
    }
}

var theName = getItemById(data['items1'], 1).name;

edited Sep 22, 2013 at 6:16

answered Sep 22, 2013 at 6:10

Jackson Ray Hamilton

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Comments

Ram · Accepted Answer · 2013-09-22 06:04:17Z

2

As items1 is array, you should write:

data.items1[0].name

edited Sep 22, 2013 at 6:04

Ram

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answered Sep 22, 2013 at 6:03

jancha

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4 Comments

Code Junkie Over a year ago

I'm going to dynamically pass in the array needed, so this wouldn't work for me.

Daedalus Over a year ago

@George Then you need to either restructure your json or create a function to find adjacent values. The first one is the easier method.

Code Junkie Over a year ago

@Daedalus do you have a better idea how to restructure my json?

jancha Over a year ago

Very simple. Put "id" as a key. Then you will be able to access data directly. E.g. data.items1.id1.name

Kelsadita · Accepted Answer · 2013-09-22 06:01:41Z

1

Try this data['items1'][0].name

answered Sep 22, 2013 at 6:01

Kelsadita

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3 Comments

Daedalus Over a year ago

Wouldn't do it, per the structure of the json.

Code Junkie Over a year ago

What does the zero stand for?

Kelsadita Over a year ago

@George: its for the first element in items1 array

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