I have a large root file, but when using pyroot, the for loop is too slow, is there any good way to deal with it?

[bellenot]

RDataFrame in python loop

Dear, I heard that RDataFrame is much efficient than classic loops, but I’m not sure how to use it for a simple code as in python: chain = ROOT.TChain() chain.Add(Dataset) h = ROOT.TH1D(“h”,"", n, x_min, x_max) lvmu1=ROOT.TLorentzVector() lvmu2 =ROOT.TLorentzVector() for ev in chain: lvmu1.SetPtEtaPhiE(ev.pt_muon[0], ev.eta_muon[0], ev.phi_muon[0], ev.E_muon[0]) lvmu2.SetPtEtaPhiE(ev.pt_muon[1], ev.eta_muon[1], ev.phi_muon[1], ev.E_muon[1]) lvmu3 = lvmu1+ lvmu2 h.Fill(lvmu3.Pt())