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import os, sys; sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", ".."))
from pattern.search import search, taxonomy, Classifier
from pattern.en import parsetree
# The search module includes a Taxonomy class
# that can be used to define semantic word types.
# For example, consider that you want to extract flower names from a text.
# This would make search patterns somewhat unwieldy:
# search("rose|lily|daisy|daffodil|begonia", txt).
# A better approach is to use the taxonomy:
for flower in ("rose", "lily", "daisy", "daffodil", "begonia"):
taxonomy.append(flower, type="flower")
print taxonomy.children("flower")
print taxonomy.parents("rose")
print taxonomy.classify("rose") # Yields the most recently added parent.
print
# Taxonomy terms can be included in a pattern by using uppercase:
t = parsetree("A field of white daffodils.", lemmata=True)
m = search("FLOWER", t)
print t
print m
print
# Another example:
taxonomy.append("chicken", type="food")
taxonomy.append("chicken", type="bird")
taxonomy.append("penguin", type="bird")
taxonomy.append("bird", type="animal")
print taxonomy.parents("chicken")
print taxonomy.children("animal", recursive=True)
print search("FOOD", "I'm eating chicken.")
print
# The advantage is that the taxonomy can hold an entire hierarchy.
# For example, "flower" could be classified as "organism".
# Other organisms could be defined as well (insects, trees, mammals, ...)
# The ORGANISM constraint then matches everything that is an organism.
# A taxonomy entry can also be a proper name containing spaces
# (e.g. "windows vista", case insensitive).
# It will be detected as long as it is contained in a single chunk:
taxonomy.append("windows vista", type="operating system")
taxonomy.append("ubuntu", type="operating system")
t = parsetree("Which do you like more, Windows Vista, or Ubuntu?")
m = search("OPERATING_SYSTEM", t)
print t
print m
print m[0].constituents()
print
# Taxonomy entries cannot have wildcards (*),
# but you can use a classifier to simulate this.
# Classifiers are quite slow but useful in many ways.
# For example, a classifier could be written to dynamically
# retrieve word categories from WordNet.
def find_parents(word):
if word.startswith(("mac os", "windows", "ubuntu")):
return ["operating system"]
c = Classifier(parents=find_parents)
taxonomy.classifiers.append(c)
t = parsetree("I like Mac OS X 10.5 better than Windows XP or Ubuntu.")
m = search("OPERATING_SYSTEM", t)
print t
print m
print m[0].constituents()
print m[1].constituents()
print
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