chain.Chain Class Reference

Inheritance diagram for chain.Chain:

Public Member Functions
def	__getattr__
def	__getitem__
def	__init__
def	__iter__
def	__len__

Public Attributes
	chain
	files

Private Member Functions
def	_guessTreeName

Detailed Description

Wrapper to TChain, with a python iterable interface.

Example of use:  #TODO make that a doctest / nose?
   from chain import Chain
   the_chain = Chain('../test/test_*.root', 'test_tree')
   event3 = the_chain[2]
   print event3.var1

   for event in the_chain:
       print event.var1

Definition at line 22 of file chain.py.

Constructor & Destructor Documentation

def chain.Chain.__init__	(		self,
			input,
			tree_name = None
	)

Create a chain.

Parameters:
  input     = either a list of files or a wildcard (e.g. 'subdir/*.root').
      In the latter case all files matching the pattern will be used
      to build the chain.
  tree_name = key of the tree in each file.
      if None and if each file contains only one TTree,
      this TTree is used.

Definition at line 35 of file chain.py.

    def __init__(self, input, tree_name=None):
        """
        Create a chain.

        Parameters:
          input     = either a list of files or a wildcard (e.g. 'subdir/*.root').
                      In the latter case all files matching the pattern will be used
                      to build the chain.
          tree_name = key of the tree in each file.
                      if None and if each file contains only one TTree,
                      this TTree is used.
        """
        self.files = input
        if isinstance(input, basestring): # input is a pattern
            self.files = glob.glob(input)
            if len(self.files)==0:
                raise ValueError('no matching file name: '+input)
        else: # case of a list of files
            if False in [
                ((is_pfn(fnam) and os.path.isfile(fnam)) or
                is_lfn(fnam)) or is_rootfn(fnam)
                for fnam in self.files]:
                err = 'at least one input file does not exist\n'
                err += pprint.pformat(self.files)
                raise ValueError(err)
        if tree_name is None:
            tree_name = self._guessTreeName(input)
        self.chain = TChain(tree_name)
        for file in self.files:
            self.chain.Add(file)