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df031_Stats.C
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1/// \file
2/// \ingroup tutorial_dataframe
3/// \notebook
4/// Use the Stats action to extract the statistics of a column.
5///
6/// Extract the statistics relative to RDataFrame columns and store them
7/// in TStatistic instances.
8///
9/// \macro_code
10/// \macro_output
11///
12/// \date April 2019
13/// \author Danilo Piparo (CERN)
14
15void df031_Stats() {
16
17 // Create a data frame and add two columns: one for the values and one for the weight.
19 auto rr = r.Define("v", [](ULong64_t e){return e;}, {"rdfentry_"})
20 .Define("w", [](ULong64_t e){return 1./(e+1);}, {"v"});
21
22 // Now extract the statistics, weighted, unweighted - with and without explicit types.
23 auto stats_eu = rr.Stats<ULong64_t>("v");
24 auto stats_ew = rr.Stats<ULong64_t, double>("v", "w");
25 auto stats_iu = rr.Stats("v");
26 auto stats_iw = rr.Stats("v", "w");
27
28 // Now print them: they are all identical of course!
29 stats_eu->Print();
30 stats_ew->Print();
31 stats_iu->Print();
32 stats_iw->Print();
33}
ROOT::R::TRInterface & r
Definition Object.C:4
#define e(i)
Definition RSha256.hxx:103
unsigned long long ULong64_t
Definition RtypesCore.h:74
ROOT's RDataFrame offers a high level interface for analyses of data stored in TTrees,...
virtual void Print(Option_t *option="") const
This method must be overridden when a class wants to print itself.
Definition TObject.cxx:552