df024_Display.py

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## \file
## \ingroup tutorial_dataframe
## \notebook
## Use the Display action to inspect entry values.
##
## This tutorial shows how to use the Display action
##
## \macro_code
## \macro_output
##
## \date August 2018
## \authors Enrico Guiraud, Danilo Piparo, Enric Tejedor Saavedra (CERN), Massimo Tumolo (Politecnico di Torino)
 
import ROOT
 
# Setting up a Dataframe with some data
ROOT.gInterpreter.ProcessLine('''
   unsigned long long y = 1;
   int x = 1;
   double w = 1;
   double z = 1;
   ROOT::RDataFrame df(10);
   auto d = df.Define("y", [&y]() { return y *= 100; }) // A column with ulongs
              .Define("x",
                      [&x]() {
                         return std::vector<int>({x++, x++, x++, x++});
                      })                                // A column with four-elements collection
              .Define("w", [&w]() { return w *= 1.8; }) // A column with doubles
              .Define("z", [&z]() {
                 z *= 1.1;
                 return std::vector<std::vector<double>>({{z, ++z}, {z, ++z}, {z, ++z}});
              }); // A column of matrices
''')
 
d = ROOT.d
 
# Preparing the RResultPtr<RDisplay> object with all columns and default number of entries
d1 = d.Display("")
# Preparing the RResultPtr<RDisplay> object with two columns and default number of entries
cols = ROOT.vector('string')(); cols.push_back("x"); cols.push_back("y");
d2 = d.Display(cols)
 
# Printing the short representations, the event loop will run
print("The following is the representation of all columns with the default nr of entries")
d1.Print()
print("\n\nThe following is the representation of two columns with the default nr of entries")
d2.Print()