Question

I want to build a directed graph and subscribe edges.

import os
import scipy as sc
import pylab
import networkx 
import matplotlib.pyplot as plt
from networkx import *
from numpy import *

G=networkx.DiGraph()
R=[('S0','S1'),('S1','S2'),('S1','S7'),('S2','S3'),('S2','S6'),('S3','S4'),('S3','S6'),('S4','S5'),('S5','S6'),('S6','S7'),('S7','S8'),('S7','S5'),('S8','Sk') ] 

G.add_edges_from([ (2,3,) ])
G.add_edges_from(R) 
networkx.draw_circular(G)

plt.show()
plt.savefig("path.png");

Now I have done this. I built a graph, but I cannot think up how to subscribe edges. For example I want to mark S0 and S1 edge like "565", etc. It will make it more visual and demostrative.
Thanks in advance!

Answer 1

Instead of layouting and drawing in one single step (networkx.draw_circular(G)), you can layout and draw nodes, edges, node labels and edge labels separately. Here’s a small example:

import networkx as nx
import matplotlib.pyplot as plt

G=nx.DiGraph()
R=[('S0','S1'),('S1','S2'),('S1','S7'),('S0','S7')] 

G.add_edges_from(R)

# Calculate layout and get all positions
pos = nx.circular_layout(G)

# Draw everything
nx.draw_networkx_nodes(G, pos)
nx.draw_networkx_edges(G, pos)
nx.draw_networkx_labels(G, pos)
nx.draw_networkx_edge_labels(G, pos, 
    {
        ('S0', 'S1'): 'edge1',
        ('S1', 'S2'): 'edge2',
        ('S1', 'S7'): 'edge3',
        ('S0', 'S7'): 'edge4'
    }
)

plt.axis('off')
plt.savefig("path.png");
plt.show()

For more information about what parameters can be passed to the different drawing functions, check the documentation.