# Roget¶

Build a directed graph of 1022 categories and 5075 cross-references as defined in the 1879 version of Roget’s Thesaurus contained in the datafile roget_dat.txt. This example is described in Section 1.2 in Knuth’s book (see [1] and [2]).

Note that one of the 5075 cross references is a self loop yet it is included in the graph built here because the standard networkx DiGraph class allows self loops. (cf. 400pungency:400 401 403 405).

## References¶

 [1] Donald E. Knuth, “The Stanford GraphBase: A Platform for Combinatorial Computing”, ACM Press, New York, 1993.

Out:

Loaded roget_dat.txt containing 1022 categories.
digraph has 1022 nodes with 5075 edges
21 connected components


from __future__ import print_function

# Authors: Brendt Wohlberg, Aric Hagberg (hagberg@lanl.gov)
# Date: 2005-04-01 07:56:22 -0700 (Fri, 01 Apr 2005)

#    Aric Hagberg <hagberg@lanl.gov>
#    Dan Schult <dschult@colgate.edu>
#    Pieter Swart <swart@lanl.gov>

import gzip
import re
import sys

import matplotlib.pyplot as plt
from networkx import nx

def roget_graph():
""" Return the thesaurus graph from the roget.dat example in
the Stanford Graph Base.
"""
# open file roget_dat.txt.gz (or roget_dat.txt)
fh = gzip.open('roget_dat.txt.gz', 'r')

G = nx.DiGraph()

line = line.decode()
continue
if line.startswith(" "):  # this is a continuation line, append
line = oldline + line
if line.endswith("\\\n"):  # continuation line, buffer, goto next
oldline = line.strip("\\\n")
continue

numfind = re.compile("^\d+")  # re to find the number of this word

for tail in tails.split():
print("skipping self loop", head, tail, file=sys.stderr)

return G

if __name__ == '__main__':
G = roget_graph()
print("digraph has %d nodes with %d edges"
% (nx.number_of_nodes(G), nx.number_of_edges(G)))
UG = G.to_undirected()
print(nx.number_connected_components(UG), "connected components")

options = {
'node_color': 'black',
'node_size': 1,
'line_color': 'grey',
'linewidths': 0,
'width': 0.1,
}
nx.draw_circular(UG, **options)
plt.show()


Total running time of the script: ( 0 minutes 0.432 seconds)

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