Question

I am new to JSON and Javasript.

I have data in JSON

var data = [
"FirstName: 'xyz', Lastname 'QSD', rollNo:'1',EntryDate:'2012-09-11T17:35:31.835+02:00'"

"FirstName: 'abc', Lastname 'qgr', rollNo:'2',EntryDate:'2012-08-11T17:35:31.835+02:00'"

]

I want to sort it according to FirstName ,or by roll no or any other attribute i choose.

Thanks in advance.

Answer 1

The first problem is the structure of your data. You have effectively an array like

var data = [ "foo", "bar" ];

and these lines of strings contain serialized data. So first we need to extract the data via any method given in this SO question, for example the JSON library method:

var interpreted = [];
for(var i=0; i<data.length; ++i) {
    interpreted[i] = JSON.parse(data[i]);
}

Now we have structures like this:

[
    0: {
        'Firstname': 'xyz',
        'Lastname' : 'QSD', // there is a colon missing in the
                            // source, I'm guessing accidentally
        ...
    },
    1: {
        'Firstname' : 'abc',
        ...
    }
]

So we can access the firstname via interpreted[i].Firstname. Now we can sort in a similar way to this other SO question, by passing sort() a comparison function:

interpreted.sort(function(a,b) { 
    if(a.Firstname == b.Firstname)
        return 0;
    if(a.Firstname > b.Firstname)
        return 1;
    else
        return -1
} );

Where you need to swap 1 and -1 if you want to sort descending.