Hi Ken, Very easy. Assuming MyCodeA a; a.fChain->GetDirectory()->ls() To get one histogram from the corresponding directory, do, eg: TH1F *h = (TH1F*)a.fChain->GetDirectory()->Get(hist_name); Rene Brun On Wed, 27 Feb 2002, Ken Bloom wrote: > Dear ROOT, > > I have two different ROOT ntuples, in two different files. I use the > MakeClass method to give me a skeleton of code that allows me to create and > fill histograms based on the contents of the two ntuples, and I can use these > classes like so: > > .L MyCodeA.C > MyCodeA a; > a.Loop(); > .L MyCodeB.C > MyCodeB b; > b.Loop(); > > By doing this, TFile objects are being created inside a and b, but I never get > to see those. > > Now, I would like to compare the histograms made by a to those made by > b. At this point, I believe I'm in a directory that belongs to b, so I can > see the histograms made by b, but seeing the ones made by a is harder. I know > that I can see a list of those histograms via something like: > > TFile* f1 = > (TFile*)gROOT->GetListOfFiles()->FindObject("/path/name/of/file"); > f1.Print(); > > but I seem to have trouble then grabbing the histograms in said list. > > So how can I get to use both sets of histograms simultaneously? And > is there a way to do this without going through gROOT? I feel like I did > things like this in PAW, and that it was much easier! Thanks, best wishes. > > Ken > > ------------------------------------------------------------------------------ > Ken Bloom, Karma Adjuster Department of Physics > 734-763-2329 / 734-936-1817 (fax) University of Michigan > kenbloom@umich.edu http://www.umich.edu/~kenbloom > >
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