parsing nested json object

Question

I have a json file that I'm trying to get values out of. One object is nested inside another in this file. I can isolate the top level values, but not the nested values. It must be a syntax issue. Here's what I'm using.

This is the json:

{
    "total": [
        [
            {
                "votes": "79,060"
            },
            {
                "percent": "11%"
            },
            {
                "winner": "0"
            }
        ],
        [
            {
                "votes": "167,800"
            },
            {
                "percent": "22%"
            },
            {
                "winner": "0"
            }
        ],
        [
            {
                "votes": "51,519"
            },
            {
                "percent": "7%"
            },
            {
                "winner": "0"
            }
        ],
        [
            {
                "votes": "297,060"
            },
            {
                "percent": "39%"
            },
            {
                "winner": "1"
            }
        ],
        [
            {
                "votes": "156,787"
            },
            {
                "percent": "21%"
            },
            {
                "winner": "0"
            }
        ]
    ],
    "useWinnerColors": 1,
    "timestamp": "3:00 p.m. April 26",
    "candidateCount": 5
}

When I write:

console.log(json.candidateCount);

I get the right answer (5).

But when I write:

console.log(json.total[0][1]);

I get Object { percent="11%"}.

And when I write:

console.log(json.total[0].votes);

I get undefined.

How do I isolate the value of the items in "total", please?

Answer 1

You're getting undefined because json.total[0] is itself, an array. You need to isolate the specific array inside json.total[0]. So you would need to do something like json.total[0][0].votes or json.total[0][1].votes.

I think a better structure for your JSON would be something like this:

{"total": [    
   {
      "votes": "79,060"
      "percent": "11%"
      "winner": "0",
   },
   ...
   {
      "votes": "156,787",
      "percent": "21%",
      "winner": "0"
   }], 
   "useWinnerColors": 1,
   "timestamp": "3:00 p.m. April 26",
   "candidateCount": 5
}

Now you can do json.total[0].votes.

You don't need to create an array where each entry is a name-value pair. You can directly use an associative-array.

EDIT: To iterate over your associative array, use for..in along with hasOwnProperty(). The hasOwnProperty() check will prevent you from iterating over properties that it has inherited (some third-party libraries pollute the namespace):

var map = json.total[0];
for(var prop in map) if(map.hasOwnProperty(prop)) {
   var value = map[prop];
   ...
}

Answer 2

Each '[' symbol means we deal with Array, each '{' - with Object. So json.total is actually an array of arrays of objects (though each inner object is just a 'tuple' - single key-value pair.

So...

json.total[0][1] - evaluates to { 'percent': '11%' }

json.total[0]['votes'] - evaluates to nothing (undefined), as one step is skipped. ) It really should be json.total[0][n].votes or json.total[0][n]['votes']. These two forms are (almost) identical. )