# Ntuples and Selections

    {
       //
       // To see the output of this macro, click  here
       //
       gROOT->Reset();
       c1 = new TCanvas("c1","The Ntuple canvas",200,10,700,780);

       gBenchmark->Start("ntuple1");
       //
       // Connect ROOT histogram/ntuple demonstration file
       // generated by example hsimple.C.
       f1 = new TFile("hsimple.root");
       //
       // Inside this canvas, we create 4 pads
       //
       pad1 = new TPad("pad1","This is pad1",0.02,0.52,0.48,0.98,21);
       pad2 = new TPad("pad2","This is pad2",0.52,0.52,0.98,0.98,21);
       pad3 = new TPad("pad3","This is pad3",0.02,0.02,0.48,0.48,21);
       pad4 = new TPad("pad4","This is pad4",0.52,0.02,0.98,0.48,1);
       pad1->Draw();
       pad2->Draw();
       pad3->Draw();
       pad4->Draw();
       //
       // Change default style for the statistics box
       gStyle->SetStatW(0.30);
       gStyle->SetStatH(0.20);
       gStyle->SetStatColor(42);
       //
       // Display a function of one ntuple column imposing a condition
       // on another column.
       pad1->cd();
       pad1->SetGrid();
       pad1->SetLogy();
       pad1->GetFrame()->SetFillColor(15);
       ntuple->SetLineColor(1);
       ntuple->SetFillStyle(1001);
       ntuple->SetFillColor(45);
       ntuple->Draw("3*px+2","px**2+py**2>1");
       ntuple->SetFillColor(38);
       ntuple->Draw("2*px+2","pz>2","same");
       ntuple->SetFillColor(5);
       ntuple->Draw("1.3*px+2","(px^2+py^2>4) && py>0","same");
       c1->Update();
       //
       // Display the profile of two columns
       // The profile histogram produced is saved in the current directory with
       // the name hprofs
       pad2->cd();
       pad2->SetGrid();
       pad2->GetFrame()->SetFillColor(32);
       ntuple->Draw("pz:px>>hprofs","","profs");
       hprofs->SetMarkerColor(5);
       hprofs->SetMarkerSize(0.7);
       hprofs->SetMarkerStyle(21);
       hprofs->Fit("pol2","","same");
       // Get pointer to fitted function and modify its attributes
       TF1 *fpol2 = hprofs->GetFunction("pol2");
       fpol2->SetLineWidth(4);
       fpol2->SetLineColor(2);
       c1->Update();
       //
       // Display a scatter plot of two columns with a selection.
       // Superimpose the result of another cut with a different marker color
       pad3->cd();
       pad3->GetFrame()->SetFillColor(38);
       pad3->GetFrame()->SetBorderSize(8);
       ntuple->SetMarkerColor(1);
       ntuple->Draw("py:px","pz>1");
       ntuple->SetMarkerColor(2);
       ntuple->Draw("py:px","pz<1","same");
       c1->Update();
       //
       // Display a 3-D scatter plot of 3 columns. Superimpose a different selection.
       pad4->cd();
       ntuple->Draw("pz:py:px","(pz<10 && pz>6)+(pz<4 && pz>3)");
       ntuple->SetMarkerColor(4);
       ntuple->Draw("pz:py:px","pz<6 && pz>4","same");
       ntuple->SetMarkerColor(5);
       ntuple->Draw("pz:py:px","pz<4 && pz>3","same");
       l4 = new TPaveText(-0.9,0.5,0.9,0.95);
       l4->SetFillColor(42);
       l4->SetTextAlign(12);
       l4->AddText("You can interactively rotate this view in 2 ways:");
       l4->AddText("  - With the RotateCube in clicking in this pad");
       l4->AddText("  - Selecting View with x3d in the View menu");
       l4->Draw();
       //
       c1->cd();
       c1->Update();
       gStyle->SetStatColor(19);
       gBenchmark->Show("ntuple1");
    }