I am (again) trying to switch my analysis codes to Root dataframes, since I have seen that Proof is going to disappear. It’s a very basic question, but after writing my dataframe to TTree using Snapshot, I would like to access the TTree pointer to Print its content.
Is there a direct way to access the TTree after Snapshot without opening the TFile and getting the TTree ? Or is there an equivalent to TTree::Print() with the dataframe ? I have seen the Display method but which seems more like a TTree::Scan
You know already that you can open the file yourself, so I won’t give details.
The other option is the Snapshot action itself (see documentation here). It returns a new RDataFrame, which is connected to the snapshotted tree. So you could write:
auto snapshotResult = myRDF.Snapshot(...);
snapshotResult->Describe()->Print();
// or
for (auto const & columnName : snapshotResult->GetColumnNames()) {
std::cout << columnName << "\n";
}
// or
auto d1 = snapshotResult->Display("");
d1->Print();