Adding data with SetBinContent

[T_man]

Hello everyone,

I have made a 2D histogram like so

TH2D* h = new TH2D("h","h",20,-10,10,20,-10,10);

and I have added some point

    h->SetBinContent(10,10,1);
    h->SetBinContent(10,10,1);
    h->SetBinContent(10,10,2);

I am expecting to see that the histogram to have 4 hits, however it is only taking the last entry of “2”, why is it not adding the hits? is there a way to do that?

[couet]

SetBinContent, as its name says, replaces the content of the bin by the given value. What you are looking for is Fill

[T_man]

How do I use Fill in this situation, when I have the x bin and y bin and the content?

[couet]

This is quite clearly explained in the reference guide in the ROOT Manual in the ROOT Primer and in the many histograms’ tutorials. Basically you should do:

    h->Fill(10,10,1);
    h->Fill(10,10,1);
    h->Fill(10,10,2);

[T_man]

Thanks that worked