Hi everyone! I have a problem filling a TString into a TTree. My code compiles, however, when I open my root file, I get the following: [ROOT Object Browser 2022-02-21 14-14-00] where some weird C++ information is filled into the TTree. Do you happen to know what the issue could be? I have gone …

{ const char *n = "trial.root"; TFile *f; TTree *t; TString s, *p; // create and fill the tree f = TFile::Open(n, "recreate"); t = new TTree("t", "t"); t->Branch("s", &s); for (Int_t i = 0; i < 10; i++) { s.Form("_%d_", i); t->Fill(); } t->Write(); t->Print(); t->Scan(); // () …

Hi, @pcanal could help you on this, but you should share the code first, so we can understand better the issue Best regards Lorenzo

Hi Lorenzo, thanks so much for the prompt reply! So, in my HistoManager.hh header file (Geant4), I define a structure: struct TreeInfo{ TTree* tree; G4String Label; G4String Title; G4bool exist; double rndmSeed; …

Hi, Thank you for sharing the code, but what is exactly the problem ? Is the string not available in the Tree ? It is not clear to me form just the snapshot of the image Lorenzo

Hi Lorenzo, So, yes. It is available but it doesn’t contain a list of particle names. Instead, when I click on it (for some reason it also has a different logo than other variables), it is filled by some strange function with red exclamation signs. [ROOT Object Browser 2022-02-21 16-27-40] [ROO…

Hi, The TString is a C++ object and you see all the data members in the TBrowser. If you want to see the actual content, you should look at the Data() leaf. Is it showing the correct content ?

Hi Lorenzo, No, unfortunately, it is empty. I just get all the data members with red exclamation marks. Vasily

@pcanal Hi! I was told you could be aware of how I may fix the issue. Do you happen to have any ideas? Thanks!!!

Hi @Wile_E_Coyote ! Thanks for the reply! Am I right that the data may have been written to my tree but I need to access it in the way that you’ve described? Also, could you please tell me what the following does: s.Form("_%d_", i); Thanks! Vasily

Hi Wile, Thanks a lot for the suggestion! I have tried to fill a TTree after formatting a TString but I still get red exclamation marks on the leaf logo when I open TBrowser. Does it mean you cannot visualize a TBranch filled by TString in the TBrowser? Thanks! Vasily

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Writing a TString into a TTree

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Wile_E_Coyote February 22, 2022, 7:25pm 11

TString::Form

Header files for Trees ROOT

“Most recent” documentation about how to generate and use an “analysis skeleton”: TTree::MakeClass (see also “ROOT User’s Guide” → “Trees” → “Using TTree::MakeClass”) TTree::MakeSelector (see also “ROOT Primer” → “File I/O and Parallel Analysis” → “N-tuples in ROOT” → “For the advanced user: Processing trees with a selector script” and “ROOT User’s Guide” → “Trees” → “Using TTree::MakeSelector” and “ROOT User’s Guide” → “Example Analysis”) TTree::MakeProxy ROOT::RDataFrame (uses the T…

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