1. from ROOT import TFile,TH1F
    2. from array import array
    4. # read a root file named data.root
    5. # it's tree name is 'tr'
    6. # branch,  strip_si,  e_si/D
    7. # branch,  e_si, e_si[16]/D
    9. h1 = TH1F('h1','',Nbins,xmin,xmax)
    10. e_si = array('d',[0]*16)
    11. h2 = [TH1F('h_{0}'.format(i),'',Nbins,xmin,xmax) for i in range(16)]
    13. f = TFile('data.root')
    14. tree = f.Get('tr')
    15. tree.GetBranch('e_si').SetAddress(e_si)
    17. entries = tree.GetEntries()
    18. for i in range(entries):
    19.     tree.GetEntry(i)
    20.     h1.Fill(tree.strip_si)
    21.     for j in range(16):
    22.         h2[j].Fill(e_si[j])
    24. tree.Draw('strip_si>>h1')