swh:1:snp:af87cd67498ef4fe47c76ed3e7caffe5b61facaf
Tip revision: 9d1aed171272a4ee709a8c585eee40fbfefbd355 authored by Fons Rademakers on 24 October 2011, 09:50:38 UTC
tag patch release v5-30-03.
tag patch release v5-30-03.
Tip revision: 9d1aed1
copytree2.C
void copytree2() {
// Example of Root macro to copy a subset of a Tree to a new Tree
// One branch of the new Tree is written to a separate file
// The input file has been generated by the program in $ROOTSYS/test/Event
// with Event 1000 1 1 1
//Author: Rene Brun
gSystem->Load("$ROOTSYS/test/libEvent");
//Get old file, old tree and set top branch address
TFile *oldfile = new TFile("$ROOTSYS/test/Event.root");
TTree *oldtree = (TTree*)oldfile->Get("T");
Event *event = new Event();
oldtree->SetBranchAddress("event",&event);
oldtree->SetBranchStatus("*",0);
oldtree->SetBranchStatus("event",1);
oldtree->SetBranchStatus("fNtrack",1);
oldtree->SetBranchStatus("fNseg",1);
oldtree->SetBranchStatus("fH",1);
//Create a new file + a clone of old tree header. Do not copy events
TFile *newfile = new TFile("small.root","recreate");
TTree *newtree = oldtree->CloneTree(0);
//Divert branch fH to a separate file and copy all events
newtree->GetBranch("fH")->SetFile("small_fH.root");
newtree->CopyEntries(oldtree);
newtree->Print();
newfile->Write();
delete oldfile;
delete newfile;
}