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import os, sys; sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", ".."))
from pattern.graph import Graph, CENTRALITY
# A graph is a network of nodes (or concepts)
# connected to each other with edges (or links).
g = Graph()
for n in ("tree", "nest", "bird", "fly", "insect", "ant"):
g.add_node(n)
g.add_edge("tree", "nest") # Trees have bird nests.
g.add_edge("nest", "bird") # Birds live in nests.
g.add_edge("bird", "fly") # Birds eat flies.
g.add_edge("ant", "bird") # Birds eat ants.
g.add_edge("fly", "insect") # Flies are insects.
g.add_edge("insect", "ant") # Ants are insects.
g.add_edge("ant", "tree") # Ants crawl on trees.
# From tree => fly: tree => ant => bird => fly
print g.shortest_path(g.node("tree"), g.node("fly"))
print g.shortest_path(g.node("nest"), g.node("ant"))
print
# Which nodes get the most traffic?
for n in sorted(g.nodes, key=lambda n: n.centrality, reverse=True):
print '%.2f' % n.centrality, n
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