Python: NetworkX

NetworkX: Adding Attributes

Attributes such as weights, labels, colors or any other property can be attached to graphs, nodes or edges.

Each graph, node and edge can hold key-value pairs of attributes. By default these are empty. But attributes can be added or changed, using add_edge() and add_node() methods, or directly manipulated.

Graph attributes

Graph attributes can be assigned when creating a new graph.

import networkx as nx G = nx.Graph(day="Friday") print(G.graph)

The output looks like this

[(1, 2, {'weight': 4.7, 'color': 'blue'}), (2, 3, {'weight': 8}), (3, 4, {'color': 'red'}), (4, 5, {'color': 'red'})] [(1, 2, {'weight': 4.7, 'color': 'blue'}), (2, 3, {'weight': 8}), (3, 4, {'color': 'red', 'weight': 4.2}), (4, 5, {'color': 'red'})]

We can also modify attributes later.

import networkx as nx G = nx.Graph(day="Friday") print(G.graph) G.graph['day'] = 'Monday' print(G.graph)

The output looks like this

{'day': 'Friday'}

{'day': 'Monday'}

Node attributes

We can add node attributes using add_node(), add_nodes_from() or nodes.

import networkx as nx G = nx.Graph() G.add_node(1, time='5pm') G.add_nodes_from([3], time='2pm') print(G.nodes[1]) G.nodes[1]['room'] = 714 print(G.nodes.data())

The output looks like this

{'time': '5pm'} [(1, {'time': '5pm', 'room': 714}), (3, {'time': '2pm'})]

Edge attributes

Similar to node attributes, we can add edge attributes using add_edge(), add_edges_from() and edges.

import networkx as nx G = nx.Graph() G.add_edge(1, 2, weight=4.7) G.add_edges_from([(3, 4), (4, 5)], color='red') G.add_edges_from([(1, 2, {'color': 'blue'}), (2, 3, {'weight': 8})]) print(G.edges.data()) G[1][2]['weight'] = 4.7 G.edges[3, 4]['weight'] = 4.2 print(G.edges.data())

The output looks like this

[(1, 2, {'weight': 4.7, 'color': 'blue'}), (2, 3, {'weight': 8}), (3, 4, {'color': 'red'}), (4, 5, {'color': 'red'})]

[(1, 2, {'weight': 4.7, 'color': 'blue'}), (2, 3, {'weight': 8}), (3, 4, {'color': 'red', 'weight': 4.2}), (4, 5, {'color': 'red'})]