Labelling a graph in python3

Question

I am trying to build a graph with networkx, using nodes as class objects. I have already labelled the nodes, but I am not being able to show labeled edges (actually, not edges at all). I was expecting to do so by defining the neighbouring nodes inside the Node class. I show my code below:

# Packages

import random as rd
import networkx as nx
from matplotlib import pyplot as plt

# Classes

class Node:
    def __init__(self, name):
        self.name = name
        self.state = rd.choice([-1, 0, 1])
        self.neighbour = None

    def get_name(self):
        return self.name
    def get_state(self):
        return self.state
    def get_neighbour(self):
        return self.neighbour

# Nodes and neighbours

n1 = Node(1)
n2 = Node(2)
n3 = Node(3)

n1.neighbour = n2
n2.neighbour = n3

# Graph

G = nx.Graph()

G.add_node(n1.name)
G.add_node(n2.name)
G.add_node(n3.name)

pos = nx.spring_layout(G)

nx.draw_networkx_nodes(G, pos)
nx.draw_networkx_edges(G, pos)
nx.draw_networkx_labels(G, pos)
#nx.draw_spectral(G, with_labels=True)   # I also tried this suggestion, but unsuccessfully

plt.savefig('jupyter_graph.png')

The reason for the "state" attribute is because I want to change the colours of the nodes depending on their state (that's another issue). The output is below:

No edges appear. Can you help me?

Answer 1

The networkx package does not create the graph based on the attributes in your Node class. The reason the values are displayed is that you pass them when adding a new node into the graph with G.add_node(n1.name) . Similarly in order to add edges you need to call to call the add_edge method. Please refer to the tutorial