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Reference Guide
df003_profiles.py
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1## \file
2## \ingroup tutorial_dataframe
3## \notebook -draw
4## This tutorial illustrates how to use TProfiles in combination with the
5## RDataFrame. See the documentation of TProfile and TProfile2D to better
6## understand the analogy of this code with the example one.
7##
8## \macro_code
9## \macro_image
10##
11## \date February 2017
12## \author Danilo Piparo
13
14import ROOT
15
16# A simple helper function to fill a test tree: this makes the example
17# stand-alone.
18def fill_tree(treeName, fileName):
19 d = ROOT.RDataFrame(25000)
20 d.Define("px", "gRandom->Gaus()")\
21 .Define("py", "gRandom->Gaus()")\
22 .Define("pz", "sqrt(px * px + py * py)")\
23 .Snapshot(treeName, fileName)
24
25
26
27# We prepare an input tree to run on
28fileName = "df003_profiles_py.root"
29treeName = "myTree"
30fill_tree(treeName, fileName)
31
32# We read the tree from the file and create a RDataFrame.
33columns = ROOT.vector('string')()
34columns.push_back("px")
35columns.push_back("py")
36columns.push_back("pz")
37d = ROOT.RDataFrame(treeName, fileName, columns)
38
39# Create the profiles
40hprof1d = d.Profile1D(("hprof1d", "Profile of pz versus px", 64, -4, 4))
41hprof2d = d.Profile2D(("hprof2d", "Profile of pz versus px and py", 40, -4, 4, 40, -4, 4, 0, 20))
42
43# And Draw
44c1 = ROOT.TCanvas("c1", "Profile histogram example", 200, 10, 700, 500)
45hprof1d.Draw()
46c2 = ROOT.TCanvas("c2", "Profile2D histogram example", 200, 10, 700, 500)
47hprof2d.Draw()
48
ROOT's RDataFrame offers a high level interface for analyses of data stored in TTrees,...
Definition: RDataFrame.hxx:42