doc/v626/df033__Describe_8py.html

import ROOT


# Create a dataframe

path = 'root://eospublic.cern.ch//eos/opendata/cms/derived-data/AOD2NanoAODOutreachTool/Run2012BC_DoubleMuParked_Muons.root'

df = ROOT.RDataFrame('Events', path)


# Describe the state of the dataframe.

# Note that this operation is not running the event loop.

# Describe returns a DFDescription object, which has e.g. a Print method. See its docs for more information.

df.Describe().Print()


# Build a small analysis studying the invariant mass of dimuon systems.

# See tutorial df102_NanoAODDimuonAnalysis for more information.

df = df.Filter('nMuon == 2')\

       .Filter('Muon_charge[0] != Muon_charge[1]')\

       .Define('Dimuon_mass', 'InvariantMass(Muon_pt, Muon_eta, Muon_phi, Muon_mass)')\

       .Filter('Dimuon_mass > 70')\

       .Range(1000)


# Trigger the event loop by asking for the mean of the dimuon mass.

print('\nApproximate mass of the Z boson: {:.2f} GeV\n'.format(

    df.Mean('Dimuon_mass').GetValue()))


# This time we ask for the `shortFormat`, which only prints a brief description of the dataset:

df.Describe().Print(shortFormat=True)

ROOT::RDataFrame
ROOT's RDataFrame offers a high level interface for analyses of data stored in TTree,...
Definition RDataFrame.hxx:50

Range
Ta Range(0, 0, 1, 1)