Scatter plot size on "tooltip"

How to retrieve the radius(or size) of a scatter plot on tooltip.

r : function(d) {

       if (d.value != null) {
            var size = datajson[k++]["total"];

            return size;
       }

I have done something like this..So the tooltip should show the size when i point on that bubble. How to achieve this?

thanks

Solution

You can add the size to the d object

r: function (d) {
    if (d.value != null) {
        var size = datajson[k++]["total"];
        d.size = size;
        return size;
    }
}

and retrieve it when you show your tooltip

tooltip: {
    contents: function (d) {
        if (d[0].value != null) {
            return d[0].size;
        }
    }
},