CODEWITHSUNDEEP
javascriptjsonidentifier
Zar
Zar

Reputation: 6882

Using number as "index" (JSON)

Recently started digging in to JSON, and I'm currently trying to use a number as "identifier", which doesn't work out too well. foo:"bar" works fine, while 0:"bar" doesn't. 

var Game = {
    status: [
                {
                    0:"val",
                    1:"val",
                    2:"val"
                },
                {
                    0:"val",
                    1:"val",
                    2:"val"
                }
           ]
}

alert(Game.status[0].0);

Is there any way to do it the following way? Something like Game.status[0].0 Would make my life way easier. Of course there's other ways around it, but this way is preferred.

Upvotes: 117

Views: 178503

Answers (7)

Amadan
Amadan

Reputation: 198314

First off, it's not JSON: JSON mandates that all keys must be strings.

Secondly, regular arrays do what you want:

var Game = {
  status: [
    [
      "val",
      "val",
      "val"
    ],
    [
      "val",
      "val",
      "val"
    ]
  }

will work, if you use Game.status[0][0]. You cannot use numbers with the dot notation (.0).

Alternatively, you can quote the numbers (i.e. { "0": "val" }...); you will have plain objects instead of Arrays, but the same syntax will work.

Upvotes: 9

Quentin
Quentin

Reputation: 943537

JSON only allows key names to be strings. Those strings can consist of numerical values.

You aren't using JSON though. You have a JavaScript object literal. You can use identifiers for keys, but an identifier can't start with a number. You can still use strings though.

var Game={
    "status": [
        {
            "0": "val",
            "1": "val",
            "2": "val"
        },
        {
            "0": "val",
            "1": "val",
            "2": "val"
        }
    ]
}

If you access the properties with dot-notation, then you have to use identifiers. Use square bracket notation instead: Game.status[0][0].

But given that data, an array would seem to make more sense.

var Game={
    "status": [
        [
            "val",
            "val",
            "val"
        ],
        [
            "val",
            "val",
            "val"
        ]
    ]
}

Upvotes: 182

5260452
5260452

Reputation: 11600

JSON is "JavaScript Object Notation". JavaScript specifies its keys must be strings or symbols.

The following quotation from MDN Docs uses the terms "key/property" to refer to what I more often hear termed as "key/value".

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Objects

In JavaScript, objects can be seen as a collection of properties. With the object literal syntax, a limited set of properties are initialized; then properties can be added and removed. Property values can be values of any type, including other objects, which enables building complex data structures. Properties are identified using key values. A key value is either a String or a Symbol value.

Upvotes: 1

Huiguorou
Huiguorou

Reputation: 397

JSON regulates key type to be string. The purpose is to support the dot notation to access the members of the object.

For example, person = {"height":170, "weight":60, "age":32}. You can access members by person.height, person.weight, etc. If JSON supports value keys, then it would look like person.0, person.1, person.2.

Upvotes: 2

zatatatata
zatatatata

Reputation: 4821

When a Javascript object property's name doesn't begin with either an underscore or a letter, you cant use the dot notation (like Game.status[0].0), and you must use the alternative notation, which is Game.status[0][0].

One different note, do you really need it to be an object inside the status array? If you're using the object like an array, why not use a real array instead?

Upvotes: 3

yatskevich
yatskevich

Reputation: 2093

Probably you need an array?

var Game = {

    status: [
        ["val", "val","val"],
        ["val", "val", "val"]
    ]
}

alert(Game.status[0][0]);

Upvotes: 6

Willem Mulder
Willem Mulder

Reputation: 13994

What about 

Game.status[0][0] or Game.status[0]["0"] ?

Does one of these work?

PS: What you have in your question is a Javascript Object, not JSON. JSON is the 'string' version of a Javascript Object.

Upvotes: 0

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