Retrieve the tree index of a point from the TGraph draw

ROOT
1

Hi rooters,
I would like to retrieve the index of a TTree event from a scatter plot.

In example after I do the

tree->Draw("y:x","various_cuts")

Is it possible from the graph I draw, right-click on a point and get his index in the tree?
I know I can get the point index of the graph in similar way to how to RemovePoint() does,
but from the i-th point of the graph there is an easy way to get the correspondent entry of the tree, or I should loop on the tree searching the entry with the same x and y?

Cheers,
Stefano

ROOT Version :6.08
Platform: Not Provided
Compiler: Not Provided

2

When the tree is Drawn the result in the TCanvas is a TGraph. There is no way to go back to the index in the tree from that TGraph. The connection with the tree is lost.

May be the highlight mode shown here might help you ?

3

Hi @couet,
I saw the new Highlight mode, unfortunately I’m working on a remote server and I cannot update root from 6.08 to 6.15.

But your answer is enough, after the points are saved in the TGraph the tree information is lost.

Thank you

Stefano