using namespace std;

Int_t readCSVfile(TString filename){
  auto csv_rdf =ROOT::RDF::FromCSV(filename.Data());

  auto date =csv_rdf.Take<TString>("date");
  auto tag =csv_rdf.Take<Long64_t>("tag");
  auto value =csv_rdf.Take<Double_t>("value");

  for(Int_t i =0;i <(Int_t)tag->size();i++){
    cout << date->at(i) << "," << tag->at(i) << "," << value->at(i) << endl;
  }  
  
  return 0;	
}