PyROOT: Getting boolean array (branch) out of tree

From: Dennis Petschull <dennis.petschull_at_cern.ch>
Date: Tue, 25 Nov 2008 14:38:18 +0100

Hi,

I'm having difficulties retrieving a branch out of a tree using PyROOT. The structure of the tree is the following:

root [0] TFile f("root_output/correl_SI_822_ALFA_32.root") root [1] f.ls()

TFile**         root_output/correl_SI_822_ALFA_32.root
 TFile*         root_output/correl_SI_822_ALFA_32.root

  KEY: TTree correl_tree;1 tree combining data from the SI telescope and ALFA root [2] correl_tree.Print()

---

*Tree :correl_tree: tree combining data from the SI telescope and ALFA *
*Entries : 50001 : Total = 71643969 bytes File Size = 4760967 *

• : : Tree compression factor = 15.10 *

  ---

  
  *Br 0 :Event : Event/I *
  *Entries : 50001 : Total Size= 201031 bytes File Size = 70483 *
  *Baskets : 7 : Basket Size= 32000 bytes Compression= 2.85 *
  *............................................................................*
  [...]
  *............................................................................*
  *Br 9 :pmfDataMD : pmfDataMD[1280]/O *
  *Entries : 50001 : Total Size= 64216248 bytes File Size = 2128067 *
  *Baskets : 2084 : Basket Size= 32000 bytes Compression= 30.16 *
  *............................................................................*
  *Br 10 :MulAFibMD : MulAFibMD[20]/I *
  *Entries : 50001 : Total Size= 4013376 bytes File Size = 554447 *
  *Baskets : 126 : Basket Size= 32000 bytes Compression= 7.23 *
  *............................................................................*
  

My python code looks like this:

#++++++++++++++++++++++++++++++++++++++++

from ROOT import TFile
from ROOT import gDirectory

file = TFile( 'root_output/correl_SI_822_ALFA_32.root' )

tree = gDirectory.Get( 'correl_tree' )
entries = tree.GetEntriesFast()

for jentry in xrange(entries):

    ientry = tree.LoadTree( jentry )
    if ientry < 0:

        break

    nb = tree.GetEntry( jentry )
    if nb <= 0:

        continue

    for nEvent in tree.pmfDataMD:

        if nEvent >= 1:
            print nEvent

#++++++++++++++++++++++++++++++++++++++++++++++++

This works for all branches except pmfDataMD ! I guess the problem lies in the boolean nature of the pmfDataMD-branch.

How do extract this boolean branch out of the tree.

Cheers,
Dennis Received on Tue Nov 25 2008 - 14:38:26 CET