Scan TTree to file

General Chat
1

Hello,

I am wondering if it is possible to scan a TTree into a text file, similar to:

tree->Scan(“*”); or tree->Scan(“var1:var2”);

, but the output is dumped into a text file rather than the terminal.

Thank you!

2

Hi Deyan,

here is an exact same question (solved): Saving output as .txt file

3

Apologies, I don’t get it. I am running a code, which first undergoes a compilation. Can it be done from within the code?

Of course, I can program my own output stream, but I wonder if this is implemented already.

4

You mean you do things like

tree->Scan("*");
tree->Scan("var1:var2");

from within a compiled executable? You mentioned the terminal, so I assumed you do it like

$ root -l
root [0] tree->Scan("*");
root [1] tree->Scan("var1:var2");
5

From compile code, you can redirect the output to a text file by calling RedirectOutput on gSystem. See ROOT: TSystem Class Reference

6

Could you try

tree->SetScanField(0);
auto logname = TString(tree->GetName())+".log";
auto player = static_cast<TTreePlayer *>(tree->GetPlayer());
player->SetScanFileName(logname);
player->SetScanRedirect(true);
tree->Scan();
7

Thank you!