How to sort JSON Array

Question

I want to show my stats from JSON file sorted by "verbruik". Now I know how to sort an array if it has like one information with it like 1 = "12313", 3 = "2124" .

I've put the whole JSON file in a variable:

for( var index in data)
                    {
                        var item = data[index];

Also could someone explain this very simply:

for (var index in data)

I know you can get use 3 parameters: value, key and index. But how does my code know which one is the value, key or index? Like when I only put index in it, it recognises it as a index and not as key.

NOTE:

I'am trying to understand and learn JQUERY and JSON, please have mercy for me.

JSON File:

{
    "46": {
        "voornaam": "Sergio",
        "achternaam": "Bloemenouw",
        "verbruik": "100000",
        "afdeling": "FHACI",
        "geslacht": "man",
        "verbruikPercentage": "18.2%"
    },
    "25": {
        "voornaam": "Chayenne",
        "achternaam": "Aalberink",
        "verbruik": "200000",
        "afdeling": "FHEHT",
        "geslacht": "vrouw",
        "verbruikPercentage": "36.4%"
    },
    "63": {
        "voornaam": "Theo",
        "achternaam": "Beijer",
        "verbruik": "50000",
        "afdeling": "FHCOM",
        "geslacht": "man",
        "verbruikPercentage": "9.1%"
    },
    "55": {
        "voornaam": "Xantha",
        "achternaam": "Dijenborgh",
        "verbruik": "80000",
        "afdeling": "FHJ",
        "geslacht": "vrouw",
        "verbruikPercentage": "14.5%"
    },
    "21": {
        "voornaam": "Steinar",
        "achternaam": "Beernink",
        "verbruik": "297000",
        "afdeling": "FHFM",
        "geslacht": "man",
        "verbruikPercentage": "54%"
    },
    "13": {
        "voornaam": "Oger",
        "achternaam": "Annevelink",
        "verbruik": "375000",
        "afdeling": "FHMER",
        "geslacht": "man",
        "verbruikPercentage": "68.2%"
    },
    "9": {
        "voornaam": "Liduin",
        "achternaam": "Bouwens",
        "verbruik": "400000",
        "afdeling": "FHMEM",
        "geslacht": "vrouw",
        "verbruikPercentage": "72.7%"
    },
    "39": {
        "voornaam": "Janique",
        "achternaam": "Brukink",
        "verbruik": "125000",
        "afdeling": "FHIBS",
        "geslacht": "vrouw",
        "verbruikPercentage": "22.7%"
    },
    "30": {
        "voornaam": "Germain",
        "achternaam": "Huisken",
        "verbruik": "180000",
        "afdeling": "JHAF",
        "geslacht": "man",
        "verbruikPercentage": "32.7%"
    },
    "5": {
        "voornaam": "Nigel",
        "achternaam": "Hoek",
        "verbruik": "400000",
        "afdeling": "Dienst IT",
        "geslacht": "man",
        "verbruikPercentage": "72.7%"
    },
    "3": {
        "voornaam": "Shelly",
        "achternaam": "Ameschot",
        "verbruik": "550000",
        "afdeling": "FHICT",
        "geslacht": "vrouw",
        "verbruikPercentage": "100%"
    },
    "61": {
        "voornaam": "Lucas",
        "achternaam": "Bernts",
        "verbruik": "60000",
        "afdeling": "FHDNP",
        "geslacht": "man",
        "verbruikPercentage": "10.9%"
    },
    "33": {
        "voornaam": "Dana",
        "achternaam": "Blokhuizen",
        "verbruik": "150000",
        "afdeling": "FYDES",
        "geslacht": "vrouw",
        "verbruikPercentage": "27.3%"
    },
    "23": {
        "voornaam": "Hidde",
        "achternaam": "Brandenborg",
        "verbruik": "250000",
        "afdeling": "FHKEE",
        "geslacht": "man",
        "verbruikPercentage": "45.5%"
    },
    "28": {
        "voornaam": "Noor",
        "achternaam": "Baek",
        "verbruik": "200000",
        "afdeling": "FOSO",
        "geslacht": "vrouw",
        "verbruikPercentage": "36.4%"
    },
    "26": {
        "voornaam": "Max",
        "achternaam": "den Diepenbroek",
        "verbruik": "200000",
        "afdeling": "FLOS",
        "geslacht": "man",
        "verbruikPercentage": "36.4%"
    },
    "27": {
        "voornaam": "Eulalie",
        "achternaam": "Kaszenborgh",
        "verbruik": "200000",
        "afdeling": "FLOT",
        "geslacht": "vrouw",
        "verbruikPercentage": "36.4%"
    },
    "32": {
        "voornaam": "Clarence",
        "achternaam": "Dolderman",
        "verbruik": "175000",
        "afdeling": "FDOO",
        "geslacht": "man",
        "verbruikPercentage": "31.8%"
    },
    "41": {
        "voornaam": "Regie",
        "achternaam": "Baankreise",
        "verbruik": "125000",
        "afdeling": "FHK",
        "geslacht": "vrouw",
        "verbruikPercentage": "22.7%"
    },
    "19": {
        "voornaam": "Ingeborg",
        "achternaam": "Aart",
        "verbruik": "350000",
        "afdeling": "MARCOM",
        "geslacht": "vrouw",
        "verbruikPercentage": "63.6%"
    },
    "47": {
        "voornaam": "Diederik",
        "achternaam": "Baajens",
        "verbruik": "100000",
        "afdeling": "FSH",
        "geslacht": "man",
        "verbruikPercentage": "18.2%"
    },
    "16": {
        "voornaam": "Fien",
        "achternaam": "Apenhorst",
        "verbruik": "350000",
        "afdeling": "FHTL",
        "geslacht": "vrouw",
        "verbruikPercentage": "63.6%"
    },
    "62": {
        "voornaam": "Dick",
        "achternaam": "Boeseken",
        "verbruik": "60000",
        "afdeling": "FHV",
        "geslacht": "man",
        "verbruikPercentage": "10.9%"
    },
    "48": {
        "voornaam": "Danielle",
        "achternaam": "Bello",
        "verbruik": "100000",
        "afdeling": "FHPM",
        "geslacht": "vrouw",
        "verbruikPercentage": "18.2%"
    },
    "70": {
        "voornaam": "Bertus",
        "achternaam": "Aelberdink",
        "verbruik": "30000",
        "afdeling": "FHHRM",
        "geslacht": "man",
        "verbruikPercentage": "5.5%"
    },
    "34": {
        "voornaam": "Manfred",
        "achternaam": "Cassenbarg",
        "verbruik": "150000",
        "afdeling": "FHPEG",
        "geslacht": "man",
        "verbruikPercentage": "27.3%"
    },
    "29": {
        "voornaam": "Jinny",
        "achternaam": "Bleeken",
        "verbruik": "200000",
        "afdeling": "FHSOC",
        "geslacht": "vrouw",
        "verbruikPercentage": "36.4%"
    },
    "49": {
        "voornaam": "Teresa",
        "achternaam": "Bresthuis",
        "verbruik": "100000",
        "afdeling": "FPZ",
        "geslacht": "vrouw",
        "verbruikPercentage": "18.2%"
    },
    "12": {
        "voornaam": "Mariska",
        "achternaam": "Borchert",
        "verbruik": "395000",
        "afdeling": "FHTNW",
        "geslacht": "vrouw",
        "verbruikPercentage": "71.8%"
    },
    "15": {
        "voornaam": "Leo",
        "achternaam": "Baggerman",
        "verbruik": "375000",
        "afdeling": "FHENG",
        "geslacht": "man",
        "verbruikPercentage": "68.2%"
    },
    "56": {
        "voornaam": "Marijn",
        "achternaam": "Dierkinck",
        "verbruik": "75000",
        "afdeling": "FHTEL",
        "geslacht": "man",
        "verbruikPercentage": "13.6%"
    },
    "6": {
        "voornaam": "Berry",
        "achternaam": "Backer",
        "verbruik": "400000",
        "afdeling": "FHBET",
        "geslacht": "man",
        "verbruikPercentage": "72.7%"
    },
    "50": {
        "voornaam": "Frederieke",
        "achternaam": "Hauser",
        "verbruik": "100000",
        "afdeling": "FHAUT",
        "geslacht": "vrouw",
        "verbruikPercentage": "18.2%"
    },
    "14": {
        "voornaam": "Marg",
        "achternaam": "Bouwhuis",
        "verbruik": "375000",
        "afdeling": "FSV",
        "geslacht": "vrouw",
        "verbruikPercentage": "68.2%"
    },
    "7": {
        "voornaam": "Ebe",
        "achternaam": "van de Braak",
        "verbruik": "400000",
        "afdeling": "DHFZ",
        "geslacht": "man",
        "verbruikPercentage": "72.7%"
    },
    "10": {
        "voornaam": "Jorrit",
        "achternaam": "Grootendorst",
        "verbruik": "400000",
        "afdeling": "DPO",
        "geslacht": "man",
        "verbruikPercentage": "72.7%"
    },
    "4": {
        "voornaam": "Desiree",
        "achternaam": "van der Kuil",
        "verbruik": "400000",
        "afdeling": "FCVB",
        "geslacht": "vrouw",
        "verbruikPercentage": "72.7%"
    },
    "18": {
        "voornaam": "Chandni",
        "achternaam": "de Kleijn",
        "verbruik": "350000",
        "afdeling": "DFIN",
        "geslacht": "vrouw",
        "verbruikPercentage": "63.6%"
    }
}

Edit:

function compareFunction(a, b) 
{
    var verbruikA = parseInt(a.verbruik);
    var verbruikB = parseInt(b.verbruik);

    if (verbruikA < verbruikB)
    {
      return -1;
    } 
    else if (verbruikA > verbruikB) 
    {
      return 1;
    } 
    else 
    {
      return 0;
    }
}
$(document).ready( function() {     

    $.ajax({
    url:"wifi_data.json",
    dataType: "json",
    success: function(data)
    {

        var item = [];
        for (var i in data) 
        {
            item.push(data[i]);
        }

        $("#container").html("<h1 id='tittel'>Top Wifi Downloaders</h1><div id='vakman'></div><p>Man</p><div id='vakvrouw'></div><p>Vrouw</p>");    



    }   
    item.sort([compareFunction]);
    });
});

Answer 1

First of all: Javascript objects are not guaranteed to be ordered. Do not rely on any perceived ordering behaviour it may show, this is dependant on implementation of the javascript engine and can change without notice.

So use an array, and put your key as a field in your object. eg

var arr = [
    {
        "id": 46,
        "voornaam": "Sergio",
        "achternaam": "Bloemenouw",
        "verbruik": "100000",
        "afdeling": "FHACI",
        "geslacht": "man",
        "verbruikPercentage": "18.2%"
    },
    {
        "id": 25,
        "voornaam": "Chayenne",
        "achternaam": "Aalberink",
        "verbruik": "200000",
        "afdeling": "FHEHT",
        "geslacht": "vrouw",
        "verbruikPercentage": "36.4%"
    }
]

Now, look at this link: Array.prototype.sort() - Javascript | MDN

The syntax is:

arr.sort([compareFunction])

If you don't specify a compareFunction, it will do a simple > comparison, which for numbers is obvious, and for strings it performs a lexical comparison. There is no defined behaviour for objects, sorting an array of objects does nothing.

So you just need to define a compareFunction :

function compareFunction(a, b) {
    var verbruikA = parseInt(a.verbruik);
    var verbruikB = parseInt(b.verbruik);

    if (verbruikA < verbruikB) {
        return -1;
    } else if (verbruikA > verbruikB) {
        return 1;
    } else {
        return 0;
    }
}

And call:

arr.sort(compareFunction);

UPDATE: If you do not have control of the source of the JSON data, then just loop through the JSON object and add them all into an array, and use that array to sort and store the sorted data:

var arr = [];
for (var i in data) {
    arr.push(data[i]);
}