Is there an easy way to grab the entry numbers from a tree after applying a cut? For example, if I have a tree with branches:
Int_t trignum
Int_t value
and I want to know the tree entry number corresponding to trignum = 20453. I could just loop over entries until I find this value, but my trees are very very large, and this would be too time consuming.
The simplest is to create a TEntryList during the application of the cut:root [1] ntuple->Draw(">>elist","px>3.0","entrylist")
(Long64_t)48
root [2] elist->Print("all")
ntuple /local2/pcanal/root_working/code/root.untouched/tutorials/hsimple.root
728
857
2485
....