This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.


edge_boundary(G, nbunch1, nbunch2=None)[source]

Return the edge boundary.

Edge boundaries are edges that have only one end in the given set of nodes.


G : graph

A networkx graph

nbunch1 : list, container

Interior node set

nbunch2 : list, container

Exterior node set. If None then it is set to all of the nodes in G not in nbunch1.


elist : list

List of edges


Nodes in nbunch1 and nbunch2 that are not in G are ignored.

nbunch1 and nbunch2 are usually meant to be disjoint, but in the interest of speed and generality, that is not required here.