#!/usr/bin/env python
class HierarchicalData(object):
"""
organizes hierarchical data as a tree.
for convenience inner nodes need not be constructed
explicitly. see examples below.
"""
def __init__(self):
# self._d stores subtrees
self._d = {}
def __getattr__(self, name):
# only attributes not starting with "_" are organinzed
# in the tree
if not name.startswith("_"):
return self._d.setdefault(name, HierarchicalData())
raise AttributeError("object %r has no attribute %s" % (self, name))
def __getstate__(self):
# for pickling
return self._d, self._attributes()
def __setstate__(self, tp):
# for unpickling
d,l = tp
self._d = d
for name,obj in l: setattr(self, name, obj)
def _attributes(self):
# return 'leaves' of the data tree
return [(s, getattr(self, s)) for s in dir(self) if not s.startswith("_") ]
def _getLeaves(self, prefix=""):
# getLeaves tree, starting with self
# prefix stores name of tree node above
prefix = prefix and prefix + "."
rv = {}
atl = self._d.keys()
for at in atl:
ob = getattr(self, at)
trv = ob._getLeaves(prefix+at)
rv.update(trv)
for at, ob in self._attributes():
rv[prefix+at] = ob
return rv
def __str__(self):
# easy to read string representation of data
rl = []
for k,v in self._getLeaves().items():
rl.append("%s = %s" % (k,v))
return "\n".join(rl)
def getLeaves(ob, pre=""):
""" getLeavess tree, returns dictionary mapping
paths from root to leafs to value of leafs
"""
return ob._getLeaves(pre)
if __name__=="__main__":
model=HierarchicalData()
# model.person is contstruted on the fly:
model.person.surname = "uwe"
model.person.name = "schmitt"
model.number = 1
print
print "access via attributes:"
print
print "model.person.surname=", model.person.surname
print "model.person.name=", model.person.name
print "model.number=", model.number
print
print "print complete model:"
print
print model
print
import pickle
o = pickle.loads(pickle.dumps(model))
print "unpickle after pickle:"
print
print o
print
print "paths from root to leaves and values at leaves:"
print
print getLeaves(o)
