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df000_simple.C File Reference

Detailed Description

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Simple RDataFrame example in C++.

This tutorial shows a minimal example of RDataFrame. It starts without input data, generates a new column x with random numbers, and finally draws a histogram for x.

// Create a data frame with 100 rows
ROOT::RDataFrame rdf(100);
// Define a new column `x` that contains random numbers
auto rdf_x = rdf.Define("x", [](){ return gRandom->Rndm(); });
// Create a histogram from `x`
auto h = rdf_x.Histo1D("x");
// At the end of this function, the histogram pointed to by `h` will be deleted.
// Draw a copy of the histogram object instead:
#define h(i)
Definition RSha256.hxx:106
R__EXTERN TRandom * gRandom
Definition TRandom.h:62
ROOT's RDataFrame offers a modern, high-level interface for analysis of data stored in TTree ,...
Double_t Rndm() override
Machine independent random number generator.
Definition TRandom.cxx:559
September 2021
Enric Tejedor (CERN)

Definition in file df000_simple.C.