Df 0 0 3_Profiles

Use TProfiles with RDataFrame.

This tutorial illustrates how to use TProfiles in combination with the RDataFrame. See the documentation of TProfile and TProfile2D to better understand the analogy of this code with the example one.

Author: Danilo Piparo (CERN)
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Thursday, June 24, 2021 at 07:10 AM.

In [ ]:
import ROOT

A simple helper function to fill a test tree: this makes the example stand-alone.

In [ ]:
def fill_tree(treeName, fileName):
    d = ROOT.RDataFrame(25000)
    d.Define("px", "gRandom->Gaus()")\
     .Define("py", "gRandom->Gaus()")\
     .Define("pz", "sqrt(px * px + py * py)")\
     .Snapshot(treeName, fileName)

We prepare an input tree to run on

In [ ]:
fileName = "df003_profiles_py.root"
treeName = "myTree"
fill_tree(treeName, fileName)

We read the tree from the file and create a RDataFrame.

In [ ]:
columns = ROOT.vector('string')()
columns.push_back("px")
columns.push_back("py")
columns.push_back("pz")
d = ROOT.RDataFrame(treeName, fileName, columns)

Create the profiles

In [ ]:
hprof1d = d.Profile1D(("hprof1d", "Profile of pz versus px", 64, -4, 4))
hprof2d = d.Profile2D(("hprof2d", "Profile of pz versus px and py", 40, -4, 4, 40, -4, 4, 0, 20))

And Draw

In [ ]:
c1 = ROOT.TCanvas("c1", "Profile histogram example", 200, 10, 700, 500)
hprof1d.Draw()
c1.SaveAs("df003_c1.png")

c2 = ROOT.TCanvas("c2", "Profile2D histogram example", 200, 10, 700, 500)
hprof2d.Draw()
c2.SaveAs("df003_c2.png")

print("Saved figures to df003_*.png")

Draw all canvases

In [ ]:
from ROOT import gROOT 
gROOT.GetListOfCanvases().Draw()