## File: isolate.py

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python-networkx 1.7~rc1-3
 `1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677` ``````# encoding: utf-8 """ Functions for identifying isolate (degree zero) nodes. """ # Copyright (C) 2004-2011 by # Aric Hagberg # Dan Schult # Pieter Swart # All rights reserved. # BSD license. import networkx as nx __author__ = """\n""".join(['Drew Conway ', 'Aric Hagberg ']) __all__=['is_isolate','isolates'] def is_isolate(G,n): """Determine of node n is an isolate (degree zero). Parameters ---------- G : graph A networkx graph n : node A node in G Returns ------- isolate : bool True if n has no neighbors, False otherwise. Examples -------- >>> G=nx.Graph() >>> G.add_edge(1,2) >>> G.add_node(3) >>> nx.is_isolate(G,2) False >>> nx.is_isolate(G,3) True """ return G.degree(n)==0 def isolates(G): """Return list of isolates in the graph. Isolates are nodes with no neighbors (degree zero). Parameters ---------- G : graph A networkx graph Returns ------- isolates : list List of isolate nodes. Examples -------- >>> G = nx.Graph() >>> G.add_edge(1,2) >>> G.add_node(3) >>> nx.isolates(G) [3] To remove all isolates in the graph use >>> G.remove_nodes_from(nx.isolates(G)) >>> G.nodes() [1, 2] For digraphs isolates have zero in-degree and zero out_degre >>> G = nx.DiGraph([(0,1),(1,2)]) >>> G.add_node(3) >>> nx.isolates(G) [3] """ return [n for (n,d) in G.degree_iter() if d==0] ``````