difference between function(d) and function(d,i)?

Question

Every D3js beginner must be going through this thought, I am pretty much sure about it.

I have been around this thing for few hours now!!!!But I don\'t

Answer 1

I hope that this example can help you. This is a complete web page where you can start playing:

Basically d is the value of the data, and i is his index. You can take a look of this example here: http://jsfiddle.net/M8nK8/