Build ROOT Ntuple from other source.
This program reads the ‘aptuple.txt’ file row by row, then creates the Ntuple by adding row by row.
import sys, os
from ROOT import TFile, TNtuple, TROOT
ofn = 'aptuple.root'
print('opening file %s ...' % ifn)
infile = open( ifn, 'r' )
lines = infile.readlines()
title = lines[0]
labels = lines[1].split()
print('writing file %s ...' % ofn)
outfile =
TFile( ofn,
'RECREATE',
'ROOT file with an NTuple' )
ntuple =
TNtuple(
'ntuple', title,
':'.join( labels ) )
for line in lines[2:]:
words = line.split()
row = map( float, words )
ntuple.Fill(*row)
outfile.Write()
print('done')
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
A simple TTree restricted to a list of float variables only.
static const TString & GetTutorialDir()
Get the tutorials directory in the installation. Static utility function.
- Author
- Wim Lavrijsen
Definition in file mrt.py.