class alphatwirl.roottree.Branch(name, array, countarray)[source]

This class encloses an array.array object, which is typically used to set the address of a branch of a ROOT TTree. This class is useful for fast access to contents of TTree.

While TTree can hold many types of data, including objects of user defined classes, this class can be used only for objects of simple types, such as Int_t, Double_t, and arrays of simple types.


Suppose jet_pt is an instance of this class and the corresponding object in TTree is an array.

>>> len(jet_pt)
>>> [v for v in jet_pt]
[127.16558074951172, 68.16969299316406, 53.75463104248047]

When the corresponding object in TTree is not an array but a simple type, the length is 1 and the only element is the value.

>>> len(mht)
>>> mht[0]
__init__(name, array, countarray)[source]


__init__(name, array, countarray)