tdf008_createDataSetFromScratch.C

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/// \file
/// \ingroup tutorial_tdataframe
/// \notebook -nodraw
/// This tutorial shows how to create a dataset from scratch with TDataFrame
/// \macro_code
///
/// \date June 2017
/// \author Danilo Piparo

void tdf008_createDataSetFromScratch()
{
   // We create an empty data frame of 100 entries
   ROOT::Experimental::TDataFrame tdf(100);

   // We now fill it with random numbers
   TRandom3 rnd(1);
   auto tdf_1 = tdf.Define("rnd", [&rnd](){return rnd.Gaus();});

   // We plot these numbers
   auto hgaus = tdf_1.Histo1D("rnd");

   // And we write out the dataset on disk
   tdf_1.Snapshot("randomNumbers", "tdf008_createDataSetFromScratch.root");

}