Ranking Number Array Values

Question

I've got an array of numbers and I'd like to display them in descending order but as a rank (1st, 2nd, 3rd, etc) instead of their number values while taking ties (equal number values) into consideration.

I've got the sorting as follows:

function mySorting(a, b) {
        a = a;
        b = b;
        return a == b ? 0 : (b < a ? -1 : 1)
    }

Which works fine with the call:

var myArray=[28,92,12,12,2];
myArray.sort(mySorting);

Can anyone point me in the right direction as to how I would then rank the values of myArray with 1st, 2nd, 3rd, etc. taking ties into account?

Thanks much in advance.

Answer 1

If you are using jQuery you can take advantage of 2 array methods $.inArray() and $.grep

Create an array of the unique values to use for rank:

var ranks = $.grep(myArray, function(item, idx) {
    return item != myArray[idx - 1];
}).reverse();/* your sort function is descending I added reverse to the ranks , remove if needed*/

Useage:

$.each(myArray, function(idx, item) {
    var rank= $.inArray( item, ranks)+1;/* index position and add one for 1st,second etc*/
    $('body').append('Rank of '+item+ ' is '+ rank+'<br>')

})

DEMO: http://jsfiddle.net/XWs5j/1/

API References:

http://api.jquery.com/jQuery.grep/

http://api.jquery.com/jQuery.inArray/

EDIT: Additional demo to create array of "ties" and modify output for values that tie

http://jsfiddle.net/XWs5j/2/