%%cpp -d
void fill_tree(const char *treeName, const char *fileName)
{
   ROOT::RDataFrame d(25000);
   d.Define("px", []() { return gRandom->Gaus(); })
      .Define("py", []() { return gRandom->Gaus(); })
      .Define("pz", [](double px, double py) { return sqrt(px * px + py * py); }, {"px", "py"})
      .Snapshot(treeName, fileName);
}

auto fileName = "df003_profiles.root";
auto treeName = "myTree";
fill_tree(treeName, fileName);

ROOT::RDataFrame d(treeName, fileName);

auto hprof1d = d.Profile1D({"hprof1d", "Profile of py versus px", 64, -4, 4}, "px", "py");
auto hprof2d =
   d.Profile2D({"hprof2d", "Profile of pz versus px and py", 40, -4, 4, 40, -4, 4, 0, 20}, "px", "py", "pz");

auto c1 = new TCanvas("c1", "Profile histogram example", 200, 10, 700, 500);
hprof1d->DrawClone();
auto c2 = new TCanvas("c2", "Profile2D histogram example", 200, 10, 700, 500);
hprof2d->DrawClone("BOX");

gROOT->GetListOfCanvases()->Draw()