Warning

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

networkx.algorithms.isolate.isolates

isolates(G)

Iterator over isolates in the graph.

An isolate is a node with no neighbors (that is, with degree zero). For directed graphs, this means no in-neighbors and no out-neighbors.

Parameters:G (NetworkX graph) Returns:An iterator over the isolates of G. Return type:iterator

Examples

To get a list of all isolates of a graph, use the list constructor:

>>> G = nx.Graph()
>>> G.add_edge(1, 2)
>>> G.add_node(3)
>>> list(nx.isolates(G))
[3]

To remove all isolates in the graph, first create a list of the isolates, then use Graph.remove_nodes_from():

>>> G.remove_nodes_from(list(nx.isolates(G)))
>>> list(G)
[1, 2]

For digraphs, isolates have zero in-degree and zero out_degre:

>>> G = nx.DiGraph([(0, 1), (1, 2)])
>>> G.add_node(3)
>>> list(nx.isolates(G))
[3]