How to get number of histograms in file

ROOT
2

Hi Kristian,

Here is an example:

void list_histos(const char *fname)
{
   TKey *key;
   TFile *f = TFile::Open(fname, "READ");
   if (!f || f->IsZombie()) {
      cout << "Unable to open " << fname << " for reading..." <<endl;
      return;
   }
   Int_t total = 0;
   TIter next((TList *)f->GetListOfKeys());
   while (key = (TKey *)next()) {
      TClass *cl = gROOT->GetClass(key->GetClassName());
      if (cl->InheritsFrom("TH1")) {
         // the following line is not needed if you only want 
         // to count the histograms
         TH1 *h = (TH1 *)key->ReadObj();
         cout << "Histo found: " << h->GetName() << " - " << h->GetTitle() << endl;
         total++;
      }
   }
   cout << "Found " << total << " Histograms" << endl;
}

Cheers, Bertrand

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