def delete_node(self, n):
try:
if len(self.succ[n])+len(self.pred[n])==1: # allowed for leaf node
DiGraph.delete_node(self,n) # deletes adjacent edge too
else:
raise NetworkXError( \
"deleting interior node %s not allowed in tree"%(n))
except KeyError: # NetworkXError if n not in self
raise NetworkXError, "node %s not in graph"%n
def delete_node(self, n):
try:
if len(self.succ[n]) + len(
self.pred[n]) == 1: # allowed for leaf node
DiGraph.delete_node(self, n) # deletes adjacent edge too
else:
raise NetworkXError( \
"deleting interior node %s not allowed in tree"%(n))
except KeyError: # NetworkXError if n not in self
raise NetworkXError, "node %s not in graph" % n
def add_edge(self, u, v=None):
if v is None: (u,v)=u # no v given, assume u is an edge tuple
if self.has_edge(u,v): return # no parallel edges
elif u in self and v in self:
raise NetworkXError, "adding edge %s-%s not allowed in tree"%(u,v)
elif u in self or v in self:
DiGraph.add_edge(self,u,v) # u->v
return
elif len(self.adj)==0: # first leaf
DiGraph.add_edge(self,u,v) # u->v
return
else:
raise NetworkXError("adding edge %s-%s not allowed in tree"%(u,v))
def add_edge(self, u, v=None):
if v is None: (u, v) = u # no v given, assume u is an edge tuple
if self.has_edge(u, v): return # no parallel edges
elif u in self and v in self:
raise NetworkXError, "adding edge %s-%s not allowed in tree" % (u,
v)
elif u in self or v in self:
DiGraph.add_edge(self, u, v) # u->v
return
elif len(self.adj) == 0: # first leaf
DiGraph.add_edge(self, u, v) # u->v
return
else:
raise NetworkXError("adding edge %s-%s not allowed in tree" %
(u, v))
def __init__(self, data=None, **kwds):
DiGraph.__init__(self, **kwds)
if data is not None:
try: # build a rooted tree
D = DiGraph()
for (child, parent) in data.par.iteritems():
D.add_edge(parent, child)
except AttributeError:
D = DiGraph(data)
except: # else nothing we can do
raise NetworkXError, "Data %s is not a rooted tree:" % data
if D.order() == D.size() + 1:
self.pred = D.pred.copy()
self.succ = D.succ.copy()
self.adj = self.succ
del D
else: # not a tree
raise NetworkXError, "Data %s is not a rooted tree:" % data
def delete_edge(self, u, v=None):
if v is None: (u, v) = u
if self.degree(u) == 1 or self.degree(v) == 1:
DiGraph.delete_edge(self, u, v)
else:
raise NetworkXError(
"deleting interior edge %s-%s not allowed in tree" % (u, v))
if self.degree(u) == 0: DiGraph.delete_node(self, u)
if self.degree(v) == 0: DiGraph.delete_node(self, v)
def delete_edge(self, u, v=None):
if v is None: (u,v)=u
if self.degree(u)==1 or self.degree(v)==1:
DiGraph.delete_edge(self,u,v)
else:
raise NetworkXError(
"deleting interior edge %s-%s not allowed in tree"%(u,v))
if self.degree(u)==0: DiGraph.delete_node(self,u)
if self.degree(v)==0: DiGraph.delete_node(self,v)
def __init__(self,data=None,**kwds):
DiGraph.__init__(self,**kwds)
if data is not None:
try: # build a rooted tree
D=DiGraph()
for (child,parent) in data.par.iteritems():
D.add_edge(parent,child)
except AttributeError:
D=DiGraph(data)
except: # else nothing we can do
raise NetworkXError, "Data %s is not a rooted tree:"%data
if D.order()==D.size()+1:
self.pred=D.pred.copy()
self.succ=D.succ.copy()
self.adj=self.succ
del D
else: # not a tree
raise NetworkXError, "Data %s is not a rooted tree:"%data