Question

I am trying to use for..in loop to access the description key/value within ‘Event’ but at the moment am not fully sure how to achieve this. First of all I used the for..in and logged this out, this returns all the top level entries in the response, how do I now drill down and pick out Event.description? I first of all thought it was data[prop].Event.description but thats not the case. Should I be using a normal for loop and then the for..in inside of this?

Here is my current code:

$(document).ready(function() {

    var data = {
        "status": "ok",
        "code": "200",
        "message": "event details",
        "data": [{
            "Event": {
                "id": "1",
                "name": "Sample Event Number 1",
                "description": "Sample Event Number 4 Description ....",
                "event_date": "2012-05-31 00:00:00",
                "Band": [{
                    "id": "1",
                    "name": "Support #1",
                    "BandsEvent": {
                        "id": "7",
                        "band_id": "2",
                        "event_id": "8",
                        "created": "2012-05-23 15:53:56",
                        "modified": "2012-05-23 15:53:56"
                    }},
                {
                    "id": "2",
                    "name": "Support #2",
                    "BandsEvent": {
                        "id": "8",
                        "band_id": "1",
                        "event_id": "8",
                        "created": "2012-05-23 15:53:57",
                        "modified": "2012-05-23 15:53:57"
                    }}]
            }},
        {
            "Event": {
                "id": "2",
                "name": "Sample Event Number 2",
                "description": "Sample Event Number 4 Description ....",
                "event_date": "2012-05-31 00:00:00",
                "Band": [{
                    "id": "2",
                    "name": "Another Crazy Band",
                    "BandsEvent": {
                        "id": "3",
                        "band_id": "2",
                        "event_id": "8",
                        "created": "2012-05-23 15:53:56",
                        "modified": "2012-05-23 15:53:56"
                    }},
                {
                    "id": "4",
                    "name": "The Band",
                    "BandsEvent": {
                        "id": "8",
                        "band_id": "1",
                        "event_id": "8",
                        "created": "2012-05-23 15:53:57",
                        "modified": "2012-05-23 15:53:57"
                    }}]

            }}]
    }


    var prop;

    for (prop in data) {
        console.log( data[prop] );
        // data.Event.description 
    }

});​

Answer 1

This should do what you want:

for (var i = 0; i < data.data.length; i++) {
    console.log(data.data[i].Event.description);        
}

I should add that the reason that your code doesn’t work is that the “prop” variable would first be “status“, then “code“, then “message” and THEN “data“. Status/code/message has no “Event” property, so therefore your code would return undefined if you’d try to access data[prop].Event. Here we pick them out specifically. And since that data.data is an array, there’s no reason to use a for .. in loop, but rather just a regular for loop.

Likewise, if you would want to print out the descriptions AND the bands, you could do the following:

for (var i = 0; i < data.data.length; i++) {
    console.log(data.data[i].Event.description + " has the following bands:"); 
    for (var j = 0; j < data.data[i].Event.Band.length; j++) {  
        console.log(data.data[i].Event.Band[j].name); 
    }       
}