Roget

构建一个有向图，包含 Roget 词库 1879 年版本中定义的 1022 个类别和 5075 个交叉引用。此示例在以下著作的第 1.2 节中描述：

Donald E. Knuth，《斯坦福图库：组合计算平台》，ACM 出版社，纽约，1993 年。http://www-cs-faculty.stanford.edu/~knuth/sgb.html

注意，5075 个交叉引用中有一个是自环，但它仍包含在此构建的图中，因为标准的 networkx DiGraph 类允许自环。(参见 400pungency:400 401 403 405)。

数据文件位于

• networkx/networkx

skipping self loop 400 400
Loaded roget_dat.txt containing 1022 categories.
DiGraph with 1022 nodes and 5075 edges
21 connected components

import gzip
import re
import sys

import matplotlib.pyplot as plt
import networkx as nx


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

    G = nx.DiGraph()

    for line in fh.readlines():
        line = line.decode()
        if line.startswith("*"):  # skip comments
            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

        (headname, tails) = line.split(":")

        # head
        numfind = re.compile(r"^\d+")  # re to find the number of this word
        head = numfind.findall(headname)[0]  # get the number

        G.add_node(head)

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

    return G


G = roget_graph()
print("Loaded roget_dat.txt containing 1022 categories.")
print(G)
UG = G.to_undirected()
print(nx.number_connected_components(UG), "connected components")

options = {
    "node_color": "black",
    "node_size": 1,
    "edge_color": "gray",
    "linewidths": 0,
    "width": 0.1,
}
nx.draw_circular(UG, **options)
plt.show()