def in_edges_iter(self, nbunch=None, keys=False):
"""Return iterator over out edges in the graph.
If the optional nbunch (container of nodes) only out edges
adjacent to nodes in nbunch will be returned.
"""
if nbunch is None: # all nodes
nh=gv.agfstnode(self.handle)
while nh is not None:
eh=gv.agfstin(self.handle,nh)
while eh is not None:
e=Edge(self,eh=eh)
if keys:
yield (e[0],e[1],e.name)
else:
yield e
eh=gv.agnxtin(self.handle,eh)
nh=gv.agnxtnode(self.handle,nh)
elif nbunch in self: # if nbunch is a single node
n=Node(self,nbunch)
nh=n.handle
eh=gv.agfstin(self.handle,nh)
while eh is not None:
e=Edge(self,eh=eh)
if keys:
yield (e[0],e[1],e.name)
else:
yield e
eh=gv.agnxtin(self.handle,eh)
else: # if nbunch is a sequence of nodes
try: bunch=[n for n in nbunch if n in self]
except TypeError:
raise TypeError("nbunch is not a node or a sequence of nodes.")
for n in nbunch:
try:
nh=Node(self,n).handle
except KeyError:
continue
eh=gv.agfstin(self.handle,nh)
while eh is not None:
e=Edge(self,eh=eh)
if keys:
yield (e[0],e[1],e.name)
else:
yield e
eh=gv.agnxtin(self.handle,eh)
raise StopIteration
def predecessors_iter(self,n):
"""Return iterator over predecessor nodes of n."""
n=Node(self,n)
nh=n.handle
eh=gv.agfstin(self.handle,nh)
while eh is not None:
(s,t)=Edge(self,eh=eh)
if s==n:
yield Node(self,t)
else:
yield Node(self,s)
eh=gv.agnxtin(self.handle,eh)
raise StopIteration