In addition to the views Graph.edges() (opens new window), and Graph.adj() (opens new window), access to edges and neighbors is possible using subscript notation.

G[1]  # same as G.adj[1]

G[1][2]

G.edges[1, 2]

You can get/set the attributes of an edge using subscript notation if the edge already exists.

G.add_edge(1, 3)
G[1][3]['color'] = "blue"
G.edges[1, 2]['color'] = "red"

Fast examination of all (node, adjacency) pairs is achieved using G.adjacency(), or G.adj.items().

提示

Note that for undirected graphs, adjacency iteration sees each edge twice.

FG = nx.Graph()
FG.add_weighted_edges_from([(1, 2, 0.125), (1, 3, 0.75), (2, 4, 1.2), (3, 4, 0.375)])
for n, nbrs in FG.adj.items():
   for nbr, eattr in nbrs.items():
       wt = eattr['weight']
       if wt < 0.5: print('(%d, %d, %.3f)' % (n, nbr, wt))

Convenient access to all edges is achieved with the edges property.

for (u, v, wt) in FG.edges.data('weight'):
    if wt < 0.5: print('(%d, %d, %.3f)' % (u, v, wt))