TDataFrame.hxx

Go to the documentation of this file.

// Author: Enrico Guiraud, Danilo Piparo CERN  12/2016

/*************************************************************************
 * Copyright (C) 1995-2016, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

/**
  \defgroup dataframe DataFrame
ROOT's TDataFrame allows to analyse data stored in TTrees with a high level interface.
*/

#ifndef ROOT_TDATAFRAME
#define ROOT_TDATAFRAME

#include "ROOT/TypeTraits.hxx"
#include "ROOT/TDataSource.hxx"
#include "ROOT/TDFInterface.hxx"
#include "ROOT/TDFNodes.hxx"
#include "ROOT/TDFUtils.hxx"
#include "TChain.h"

#include <memory>
#include <iosfwd> // std::ostringstream
#include <stdexcept>
#include <string>
class TDirectory;
class TTree;

namespace ROOT {
namespace Experimental {
namespace TDFDetail = ROOT::Detail::TDF;
namespace TDFInternal = ROOT::Internal::TDF;
namespace TTraits = ROOT::TypeTraits;

class TDataFrame : public TDF::TInterface<TDFDetail::TLoopManager> {
   using ColumnNames_t = TDFDetail::ColumnNames_t;
   using TDataSource = ROOT::Experimental::TDF::TDataSource;
public:
   TDataFrame(std::string_view treeName, std::string_view filenameglob, const ColumnNames_t &defaultBranches = {});
   TDataFrame(std::string_view treename, const std::vector<std::string> &filenames,
              const ColumnNames_t &defaultBranches = {});
   TDataFrame(std::string_view treeName, ::TDirectory *dirPtr, const ColumnNames_t &defaultBranches = {});
   TDataFrame(TTree &tree, const ColumnNames_t &defaultBranches = {});
   TDataFrame(ULong64_t numEntries);
   TDataFrame(std::unique_ptr<TDataSource>, const ColumnNames_t &defaultBranches = {});
};

} // end NS Experimental
} // end NS ROOT

////////////////////////////////////////////////////////////////////////////////
/// Print a TDataFrame at the prompt:
namespace cling {
inline std::string printValue(ROOT::Experimental::TDataFrame *tdf)
{
   auto df = tdf->GetDataFrameChecked();
   auto *tree = df->GetTree();
   auto defBranches = df->GetDefaultColumnNames();

   std::ostringstream ret;
   if (tree) {
      ret << "A data frame built on top of the " << tree->GetName() << " dataset.";
      if (!defBranches.empty()) {
         if (defBranches.size() == 1)
            ret << "\nDefault branch: " << defBranches[0];
         else {
            ret << "\nDefault branches:\n";
            for (auto &&branch : defBranches) {
               ret << " - " << branch << "\n";
            }
         }
      }
   } else {
      ret << "A data frame that will create " << df->GetNEmptyEntries() << " entries\n";
   }

   return ret.str();
}
} // namespace cling

#endif // ROOT_TDATAFRAME