JQuery DataTables – Row Grouping, Sum, Collapsible, Export

"drawCallback": function ( settings ) {
	var api = this.api(),data;
	var rows = api.rows( {page:'current'} ).nodes();
	var last=null;
	
	// Remove the formatting to get integer data for summation
	var intVal = function ( i ) {
		return typeof i === 'string' ?
			i.replace(/[\$,]/g, '')*1 :
			typeof i === 'number' ?
				i : 0;
	};

	total=new Array();
	api.column(2, {page:'current'} ).data().each( function ( group, i ) {
	    group_assoc=group.replace(' ',"_");
        if(typeof total[group_assoc] != 'undefined'){
            total[group_assoc]=total[group_assoc]+intVal(api.column(5).data()[i]);
        }else{
            total[group_assoc]=intVal(api.column(5).data()[i]);
        }
		if ( last !== group ) {
			$(rows).eq( i ).before(
				'<tr class="group"><td colspan="4">'+group+'</td><td class="'+group_assoc+'"></td></tr>'
			);
			
			last = group;
		}
	} );
    for(var key in total) {
        $("."+key).html("$"+total[key]);
    }
}