This isn't a single JSON object. You have an array of JSON objects. You need to loop over array first and then access each object. Maybe the following kickoff example is helpful:
var arrayOfObjects = [{
"id": 28,
"Title": "Sweden"
}, {
"id": 56,
"Title": "USA"
}, {
"id": 89,
"Title": "England"
}];
for (var i = 0; i < arrayOfObjects.length; i++) {
var object = arrayOfObjects[i];
for (var property in object) {
alert('item ' + i + ': ' + property + '=' + object[property]);
}
// If property names are known beforehand, you can also just do e.g.
// alert(object.id + ',' + object.Title);
}
If the array of JSON objects is actually passed in as a plain vanilla string, then you would indeed need eval() here.
var string = '[{"id":28,"Title":"Sweden"}, {"id":56,"Title":"USA"}, {"id":89,"Title":"England"}]';
var arrayOfObjects = eval(string);
// ...
To learn more about JSON, check MDN web docs: Working with JSON .
Answer from BalusC on Stack OverflowThis isn't a single JSON object. You have an array of JSON objects. You need to loop over array first and then access each object. Maybe the following kickoff example is helpful:
var arrayOfObjects = [{
"id": 28,
"Title": "Sweden"
}, {
"id": 56,
"Title": "USA"
}, {
"id": 89,
"Title": "England"
}];
for (var i = 0; i < arrayOfObjects.length; i++) {
var object = arrayOfObjects[i];
for (var property in object) {
alert('item ' + i + ': ' + property + '=' + object[property]);
}
// If property names are known beforehand, you can also just do e.g.
// alert(object.id + ',' + object.Title);
}
If the array of JSON objects is actually passed in as a plain vanilla string, then you would indeed need eval() here.
var string = '[{"id":28,"Title":"Sweden"}, {"id":56,"Title":"USA"}, {"id":89,"Title":"England"}]';
var arrayOfObjects = eval(string);
// ...
To learn more about JSON, check MDN web docs: Working with JSON .
This is your dataArray:
[
{
"id":28,
"Title":"Sweden"
},
{
"id":56,
"Title":"USA"
},
{
"id":89,
"Title":"England"
}
]
Then parseJson can be used:
$(jQuery.parseJSON(JSON.stringify(dataArray))).each(function() {
var ID = this.id;
var TITLE = this.Title;
});
Videos
Lean towards option 1, as it's a more expected format.
Option 1 works with JSON as it's designed to be used and therefore benefits from what JSON offers (a degree of human readability, which is good for debugging, and straightforward parsing, which is good for limiting entire categories of bugs to begin with).
Option 2 begrudgingly adopts JSON and subverts many of the benefits. If you don't want human readability, use protobuf or something similar... AIWalker's "CSV"-like approach isn't terrible either. It is marginally better (readable) than splitting objects apart and recombining them. But, this is still not as good (readable) as using JSON "as designed".
Also bear in mind, your API responses are also likely going to be gzipped. Most of the repetition in option 1 will be quickly and transparently condensed over the wire.
As an aside, if you're moving a lot of data, also consider JSONL or paginated results. Pagination can be especially helpful for web clients, as it places natural pauses in the processing, providing a degree of "organic" protection against UI lockups.
A list of objects is easier to work with. You can use append, map, filter... All the nice things JS Arrays have which manual indexing doesn't. And there's no way to get out of sync, so that's an entire class of bugs gone.
If you're worried about efficiency:
- Measure (premature optimization is the root of all evil)
- Consider the list of lists trick AIWalker proposed
- Consider an outright binary format
- Make sure gzip is enabled
- Measure (it's worth saying twice)
// You can declare restaurants as an array of restaurant objects
restaurants =
[
{
"location" : "123 Road Dr",
"city_state" : "MyCity ST",
"phone" : "555-555-5555",
"distance" : "1"
},
{
"location" : "456 Avenue Crt",
"city_state" : "MyTown AL",
"phone" : "555-867-5309",
"distance" : "0"
}
];
// Then operate on them with a for loop as such
for (var i = 0; i< restaurants.length; i++) {
restaurants[i].distance = restaurants[i].distance; // Or some other logic.
}
// Finally you can sort them using an anonymous function like this
restaurants.sort(function(a,b) { return a.distance - b.distance; });
First of all, this is not JSON at all, you are just using Javascript objects. JSON is a text format for representing objects, there is no such thing as a "JSON object".
You can create a constructor for your objects like this:
function Restaurant(location, city_state, phone, distance) {
this.location = location;
this.city_state = city_state;
this.phone = phone;
// here you can add some logic for the distance field, if you like:
this.distance = distance;
}
// create an array restaurants
var restaurants = [];
// add objects to the array
restaurants.push(new Restaurant("123 Road Dr", "MyCity ST", "555-555-5555", 0));
restaurants.push(new Restaurant("123 Road Dr", "MyCity ST", "555-555-5555", 0));
restaurants.push(new Restaurant("123 Road Dr", "MyCity ST", "555-555-5555", 0));
var json_data = {"2013-01-21":1,"2013-01-22":7};
var result = [];
for(var i in json_data)
result.push([i, json_data [i]]);
var data = new google.visualization.DataTable();
data.addColumn('string', 'Topping');
data.addColumn('number', 'Slices');
data.addRows(result);
http://jsfiddle.net/MV5rj/
If you have a well-formed JSON string, you should be able to do
var as = JSON.parse(jstring);
I do this all the time when transfering arrays through AJAX.
