SIP_get.py

import fileinput
import networkx as nx

g = nx.Graph() # 無向グラフ

file = "sample.txt"
# file = "facebook_combined.txt"
for line in fileinput.input(file):
  edge = list(map(int, line.split()))
  g.add_edge(edge[0], edge[1])

cutoff = 2
pair = nx.all_pairs_shortest_path_length(g, cutoff) 

node_dic = {}
size = len(g)

nodes = list(pair.keys())
for i in range(size):
  doc = []
  for node,distance in pair[nodes[i]].items():
    if distance == cutoff:
      doc.append(node)
    else:
      doc.extend([node]*cutoff)
  node_dic[nodes[i]] = doc

for k,v in node_dic.items():
  print(k, ",".join(map(str, v)))