Hi roottalk, I have a question about using TRefArray objects in the TTree::Draw method. In the $ROOTSYS/test/Event example, there is a datamember: TRefArray *fHighPt; // array of High Pt tracks only in the Event class that is filled with references to a subset of the tracks stored in the TClonesArray *fTracks; //->array with all tracks array. After running the executable "Event" to generate an output file Event.root, I am able to open this file in a root session and plot datamembers of the fTracks array, e.g. t -> Draw("fEvtHdr.GetEvtNum()","fTracks[0].GetPx()>0"); works and plots a histogram of event numbers for all events in which the first track has a positive Px. But if I try to use the fHighPt TRefArray in a similar way,e.g. t -> Draw("fEvtHdr.GetEvtNum()","((Track*)fHighPt->At(0))->GetPx()>0"); I receive the error message: Error in <TTreeFormula::DefinedVariable>: Unknown method:At(0).).GetPx() *ERROR 26 : Unknown name : "((Track*)fHighPt.At(0)).GetPx()" So, I'm wondering, what is the correct way to use the fHighPt branch in the TTree::Draw, TTree::Scan, etc.? Thanks for the help, -Sue
This archive was generated by hypermail 2b29 : Sat Jan 04 2003 - 23:51:15 MET