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.
opening file /home/sftnight/build/workspace/root-makedoc-v618/rootspi/rdoc/src/v6-18-00-patches.build/tutorials/pyroot/aptuple.txt ...
writing file aptuple.root ...
done
import sys, string, os
from ROOT import TFile, TNtuple
ifn = os.path.expandvars("${ROOTSYS}/tutorials/pyroot/aptuple.txt")
ofn = 'aptuple.root'
print 'opening file', ifn, '...'
infile =
open( ifn,
'r' )
lines = infile.readlines()
title = lines[0]
labels = string.split( lines[1] )
print 'writing file', ofn, '...'
outfile =
TFile( ofn,
'RECREATE',
'ROOT file with an NTuple' )
ntuple =
TNtuple(
'ntuple', title, string.join( labels,
':') )
for line in lines[2:]:
words = string.split( line )
row = map( float, words )
apply( 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.
- Author
- Wim Lavrijsen
Definition in file mrt.py.