[FIXED] Drawing a community in networkx, anything I am doing incorrectly?

Issue

Trying to do something like this but I am not sure what I am doing incorrectly

import networkx as nx
import matplotlib.pyplot as plt
import networkx.algorithms.community as nxcom

G = nx.karate_club_graph()
greedy = nxcom.greedy_modularity_communities(G) 
#returns a list with type frozen sets within the list
#[{set1},{set2},{set3}]

pos = nx.spring_layout(G)  # compute graph layout
plt.axis('off')
nx.draw_networkx_nodes(G, pos, cmap=plt.cm.RdYlBu, node_color=list(greedy.values()))
plt.show(G)

Solution

It looks like your issue comes from the way you are mapping colors to your communities. Since the node_color argument from nx.draw_networkx_nodes is expected to be a list of color (see doc here), you will need to associate each one of your nodes with the color of its community. You can do that by using:

c=plt.cm.RdYlBu(np.linspace(0,1,len(greedy))) #create a list of colors, one for each community
colors={list(g)[j]:c[i] for i,g in enumerate(greedy) for j in range(len(list(g)))} #associate each node with the color of its community
colors_sort=dict(sorted(colors.items())) #sort the dictionary by keys such

You can then convert the values of your sorted dictionnary into a list and pass it to the nx.draw_networkx_nodes with nx.draw_networkx_nodes(G, pos,node_color=list(colors_sort.values())).

See full code below:

import networkx as nx
import matplotlib.pyplot as plt
import networkx.algorithms.community as nxcom
import numpy as np

G = nx.karate_club_graph()
greedy = nxcom.greedy_modularity_communities(G) 
c=plt.cm.RdYlBu(np.linspace(0,1,len(greedy)))
colors={list(g)[j]:c[i] for i,g in enumerate(greedy) for j in range(len(list(g)))}
colors_sort=dict(sorted(colors.items()))
pos = nx.spring_layout(G)
nx.draw_networkx_nodes(G, pos,node_color=list(colors_sort.values()))
nx.draw_networkx_edges(G, pos)
nx.draw_networkx_labels(G, pos,labels={n:str(n) for n in G.nodes()})
plt.axis('off')
plt.show(G)

Answered By - jylls