ego graph
---------
>>> import networkx as nx
>>> G=nx.star_graph(3)
>>> H=nx.ego_graph(G,0)
>>> print nx.is_isomorphic(G,H)
True
>>> G.add_edge(1,11)
>>> G.add_edge(2,22)
>>> G.add_edge(3,33)
>>> H=nx.ego_graph(G,0)
>>> print nx.is_isomorphic(nx.star_graph(3),H)
True
>>> G=nx.path_graph(3)
>>> H=nx.ego_graph(G,0)
>>> print H.edges()
[(0, 1)]

