How to deal with the errors about GetEntry

[wolfram420]

Hi,
I have some problems while trying to copy entries from the branch “D0_M” of the old tree ‘t0’ and put them into a new tree named ‘t1’.

here is the error output:
Traceback (most recent call last):
File “/users/c/Desktop/simp.py”, line 18, in
t0.GetEntry(entry)
TypeError: int TTree::GetEntry(Long64_t entry, Int_t getall = 0) =>
TypeError: could not convert argument 1 (int/long conversion expects an integer object)

here is the code:
from array import array

import ROOT

f0 = ROOT.TFile.Open(“p1.root”,“READ”)

t0 = f0.Get(“DecayTree”)

t0.SetBranchStatus(“*”,0)

t0.SetBranchStatus(“D0_M”,1)

f1 = ROOT.TFile.Open(“simplify.root”, “RECREATE”)

t1 = ROOT.TTree(“tree”, “newt”)

Provide a one-element array, so ROOT can read data from this memory.

var = array(‘f’, [ 0 ])

t1.Branch(“branch0”, var, “mass”)

for entry in t0:

t0.GetEntry(entry)

t1.Fill()

Now write the header

t1.Write()

Thanks in advance,

Cheers,
Lisa

[dastudillo]

Check out the first PyROOT example on the TTree documentation (search for PyROOT on that page); it shows exactly how to get values from the tree the way you are trying (basically x = entry.branch_name inside the loop, no need for GetEntry); you can find more there, as well as in the tree Tutorials.

[wolfram420]

Thanks for your reply