Render column function(data,type,full) on Jquery datatable with complex header not working

I am new to jquery and trying to design a datatable from json response with complex header.

So far data is populated as per requirement but now I want to change some of the column data inside the same datatable based on the json data or based on other column data.

In a simple jquery datatable the facility of render columns with the use of function(data,type,full) was helpful to access other columns by writing full[columnIndex], but on complex header datatable its not working and giving undefined value.

Please help me and let me know what code should I write in order to get dynamic access to other columns of the datatable.

Here is my code :

$('#example').dataTable({
    "responsive": true,
    "aaData": data,
    "aoColumns": [{
            "sTitle": "EVENT ID",
            "defaultContent": "",
            "mData": "eventId",
            "render": function(val, type, full) {
                //alert("event id :: " + val + "  ::: " + full[0]+"  ::: "  );
                return '<td id=event>' + val + '</td>';
            }
        },
        { "mData": "ecid_1.ecid" },
        { "mData": "ecid_1.name" },
        { "mData": "ecid_1.address" },
        { "mData": "ecid_2.ecid" },
        { "mData": "ecid_2.name" },
        { "mData": "ecid_2.address" },
        {
            "sTitle": "EVENT DATE",
            "defaultContent": ""
        },
        {
            "defaultContent": "",
            "render": function(val, type, full) {
                var event = full[0];
                //data[0].eventId
                alert(event);
                if (val == "" || val == null) {
                    //alert('<input align="left" id="radio1" type="radio" name="action'+i+'" value="Approve">Approve</input><br/><input align="left" id="radio2" type="radio" name="action'+i+'" value="Reject">Reject</input>');
                    return '<input align="left" id="radio1" type="radio" name="action" value="Approve" onclick="updateEvent(&#39;' + event + '&#39;,&#39;' + full[1] + '&#39;,&#39;approve&#39;,&#39;' + full[4] + '&#39;,&#39;' + +'&#39;);">Approve</input><br/><input align="left" id="radio2" type="radio" name="action" value="Reject" onclick="updateEvent(&#39;' + event + '&#39;,&#39;' + full[1] + '&#39;,&#39;reject&#39;,&#39;' + full[4] + '&#39;,&#39;' + +'&#39;);">Reject</input>';
                } else {
                    return val;
                }
                //alert("action:::"+data);
            }
        },
        {
            "sTitle": "ACTION DATE",
            "defaultContent": ""
        },
        {
            "sTitle": "ACTION COMMENTS",
            "defaultContent": "",
            "render": function(data, type, full) {
                if (full[4] == "" || full[4] == null) {
                    //alert('<input align="left" id="radio1" type="radio" name="action'+i+'" value="Approve">Approve</input><br/><input align="left" id="radio2" type="radio" name="action'+i+'" value="Reject">Reject</input>');
                    return '<textarea  id="comment" type="text" name="comment" value"aaa"></textarea>';
                } else {
                    return '<textarea readonly style="background-color:#D3D3D3;"  id="comment" name="comment">' + data + '</textarea>';
                }
                //alert("action:::"+data);
            }
        },
        {
            "render": function(data, type, full) {
                var table = $('#example').DataTable();
                var rowIndex = $(this).closest('tr').index();
                //alert(full[2]);
                return '<a href="/MatchMergeAPI/jsp/details.jsp#someRoute?ecid1=' + full[1] + '&ecid2=' + full[2] + '&event=' + full[0] + '"><img src="/MatchMergeAPI/img/eventDetails.jpeg" alt="" style="width: 120px; height: 50px;" /></a>';
            }
        }
    ]
});

My datatable now looks like this:

Where you can see the ACTION column which is supposed to give a radio button as per render function but now giving array of data