示例#1
0
    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
示例#2
0
 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