Hi, To be more specific, in the latest Users Guide (v3.1a) at http://root.cern.ch/root/RootDoc.html you can find 35 examples of the TTree::Draw command. Many of the examples are covering arrays. These are in the chapter on Trees on page 249 (v3.1b) and pg 243 (v3.1a). Suzanne ----- Original Message ----- From: "Rene Brun" <Rene.Brun@cern.ch> To: "Volker Buescher" <buescher@fnal.gov> Cc: <roottalk@pcroot.cern.ch> Sent: Wednesday, June 20, 2001 10:01 AM Subject: Re: [ROOT] multiple arrays in TTree::Draw > Hi Volker, > What you want is already there in Root version 3.01. > There are many examples of this type in the documentation. > > Rene Brun > > On Wed, 20 Jun 2001, Volker Buescher wrote: > > > > > Hi All, > > > > I keep running into an apparent limitation of the Draw method of TTree, > > and I would appreciate very much any advice on whether this is possible in > > root or whether it could be added in future versions. Here is an example > > of what I'm trying to do: > > I have two branches, each with several variable length arrays, > > e.g. arrays mc_pt[nmc], mc_eta[nmc] in one branch and reco_pt[nreco], > > reco_eta[nreco] in the other branch. Now I'd like to use Draw() on the > > command line to plot for each event a) every entry in mc_pt versus every > > entry in reco_pt and b) same as in a) but apply cuts like > > "abs(mc_eta-reco_eta)<0.1", such that only those pairs of mc_pt/reco_pt > > are plotted, for which that condition is true. > > > > As far as I understand, root only allows to plot pairs > > > > (mc_pt[0],reco_pt[0]) > > (mc_pt[1],reco_pt[1]) > > (mc_pt[2],reco_pt[2]) > > ... > > > > rather than all possible combinations - did I overlook something? Is there > > a way to do this without the inconvenience of using Loop()? If not, > > would it be possible to add this feature? > > > > Thanks! > > Volker > > > >
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