Question

I am trying to parse this test.json (It does validates, so that doesn’t appear to be an issue, it’s in the same folder as the file containing the javascript below)

{
"mainunit": {
    "sensors": [
        {
            "id": "C9",
            "name": "Sensor 2",
            "tc": 71.3,
            "pair": null
        },
        {
            "id": "4A",
            "name": "Sensor 1",
            "tc": 106.7,
            "pair": null
        }
    ],
    "fans": null
}}

I’m trying to use this . . .

$.getJSON('test.json',function(data) {
$.each(data, function(i, learning) {

    alert(learning.mainunit.sensors[0].tc);

});});

This code is from a previous SO question, see link below.

I also have a general questions about this previous question regarding parsing json with jQuery.

Parse JSON in jquery

I can get this example to parse, but if I remove the beginning and ending square brackets it won’t parse. Can someone clarify why. It appears that json doesn’t need beginning and ending square brackets.

Thanks in advance.

Answer 1

The JSON data (which is an object) only contains one element: mainunit.

You don’t need the $.each. Just do:

data.mainunit.sensors[0].tc; // 71.3

Your $.each will loop just once, and in that loop learning will be data.mainunit.

$.each(data, function(i, learning) {
    alert(i); // 'mainunit'
    alert(data.sensors[0].tc); // 71.3
});

EDIT: To loop through each sensor:

$.each(data.mainunit.sensors, function(i, sensor) {
    alert(sensor.tc);
});