How to call back histograms and their features with unknown name?

[Wile_E_Coyote]

How to get number of histograms in file

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 wan…

A problem writing histograms to a file

If you still have problems, attach your “ww_nocut-1.root” file here for inspection. #include "TH1.h" #include "TFile.h" #include "TDirectory.h" #include "TCollection.h" #include "TKey.h" #include "TClass.h" #include "TROOT.h" #include <iostream> #include <string> #include <vector> void Normalize(TH1 *h, Double_t norm) { if ((!h) || (norm == 0.)) return; // just a precaution Double_t integral = h->Integral(); if (integral != 0.) h->Scale(norm / integral); else std::cout << h->GetName()…

Draw("COLZ") is not producing a histogram with the expected color scheme

Hello Experts, I the macro shown below, I loop over a root file that has both TH1 and TH2 histograms. I was to plot these histograms in the order they appear in the file. Over all, the macro achieves that goal, but there is one thing that the macro is not doing as expected. For the TH2 histogram, I set h2->Draw("COLZ"), but the 2D histograms that are saved in the output pdf file do not have a COLZ color scheme. Attached is an image of a sample output. The 1D histograms look exactly as I expecte…