Add edge-weights to plot output in networkx

smilingbuddha picture smilingbuddha · Feb 6, 2015 · Viewed 41.4k times · Source

I am doing some graph theory in python using the networkx package. I would like to add the weights of the edges of my graph to the plot output. How can I do this?

For example How would I modify the following code to get the desired output?

import networkx as nx
import matplotlib.pyplot as plt

G=nx.Graph()
i=1
G.add_node(i,pos=(i,i))
G.add_node(2,pos=(2,2))
G.add_node(3,pos=(1,0))
G.add_edge(1,2,weight=0.5)
G.add_edge(1,3,weight=9.8)
pos=nx.get_node_attributes(G,'pos')
nx.draw(G,pos)
plt.savefig("path.png")

I would like 0.5 and 9.8 to appear on the edges to which they refer in the graph.

Answer

Marcus Müller picture Marcus Müller · Feb 6, 2015

You'll have to call nx.draw_networkx_edge_labels(), which will allow you to... draw networkX edge labels :)

EDIT: full modified source

#!/usr/bin/python
import networkx as nx
import matplotlib.pyplot as plt

G=nx.Graph()
i=1
G.add_node(i,pos=(i,i))
G.add_node(2,pos=(2,2))
G.add_node(3,pos=(1,0))
G.add_edge(1,2,weight=0.5)
G.add_edge(1,3,weight=9.8)
pos=nx.get_node_attributes(G,'pos')
nx.draw(G,pos)
labels = nx.get_edge_attributes(G,'weight')
nx.draw_networkx_edge_labels(G,pos,edge_labels=labels)
plt.savefig(<wherever>)