The way you were doing it in GetValue.C
is totally fine. RDataFrame
can count entries but it does not offer a method to retrieve the number directly from TTree.
With RDF, you can use Take
:
auto vectorPtr = df.Take<double>("columnName");
vectorPtr
is a RResultPtr<std::vector<double>>
, i.e. a pointer to your vector.
Cheers,
Enrico