How to get a histogram in a ROOT file without knowing its full name

[Wile_E_Coyote]

Finding List of TTrees in TFile

Hi Jeff, this might get you started (I slightly modified your code): TFile *file = new TFile("myfile.root"); file->ls(); TList *list = file->GetListOfKeys(); TIter iter(list->MakeIterator()); while(TObject* obj = iter()){ TKey* theKey = (TKey*)obj; cout<< "name/type of Key is: "<<theKey->GetName() << " / " << theKey->GetClassName() << endl; theKey->Class()->Dump(); } Cheers, Danilo

Get the name of histogram

[quote=“tayyebb”]No, for example we have this code : { TFile *f = new TFile(“myfile.root”); TH1F * h1 = new TH1F(“h1”,“h1 title” , 100, 0, 4); h1 = (TH1F*)f.Get([color=#FF0000]hist1[/color]); h1->Draw(); } I want to retrieve the name of the histogram that exists in the root file ?[/quote] Start by getting the list of objects from the file then iterate over the list and check if the objects are histograms string name; for(int i=0;i < list->Getsize();i++) { TObject *obj = (TObject*)l…

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…