python networkx writefile undirected-graph

Write a Graph into a file in an adjacency list form [mentioning all neighbors of each node in each line]

I need to write a graph in a text file where each line of the file is composed from one node followed by all its neighbors. It's basically what an Adjacency List is, and what the function write_adjlist is supposed to do. Unfortunatly it's not the case, as the edge are not replicated. In the exemple of wikipedia the adjacency list is :

a adjacent to b, c

b adjacent to a, c

c adjacent to a, b

We can see that all edges are present two times (the edge (a,b) in lines 1 and 2, the edge (b,c) in lines 2 and 3...).

But now if I use the following code to generate a small world network :

import networkx as nx

N=5  #Number of nodes
v=2  #Number of neighbours
p=.1 #rewiring proba

G = nx.connected_watts_strogatz_graph(N,v,p)
nx.write_adjlist(G.to_undirected(),"test.txt")

it gives me :

#adj.py
# GMT Thu Jan 21 06:57:29 2016
# watts_strogatz_graph(5,2,0.1)
0 1 4
1 2
2 3
3 4
4

where I would like to have

Do you know how I could do to have the output I want?

Solution

Actually this is how the write_adjlist is defined so in order to have the file written as you want a simple work around can be done with the following function:

def adj_list_to_file(G,file_name):
    f = open('tst.txt', "w")
    for n in G.nodes():
        f.write(str(n) + ' ')
        for neighbor in G.neighbors(n):
            f.write(str(neighbor) + ' ')
        f.write('\n')

N=5  #Number of nodes
v=2  #Number of neighbours
p=.1 #rewiring proba
G = nx.connected_watts_strogatz_graph(N,v,p)
nx.draw(G, with_labels= True)
plt.show()
adj_list_to_file(G.to_undirected(),"tst.txt")

The file output is: