English plurals experiment

english_plurals.py

#!/usr/bin/env python
"""
Experiment with automatic generation of English plurals.
"""
import os
import random


def main():
    total_count = 0
    correct_count = 0

    while True:
        count = raw_input("Words in the sample: ")
        if not count:
            break

        try:
            count = int(count)
        except ValueError:
            continue

        sample = sample_words(count)
        for pair in sample:
            verdict = None
            while not verdict:
                verdict = raw_input("%s -> %s ? " % pair)
            if verdict.lower() == 'y':
                correct_count += 1
            total_count += 1

    if not total_count:
        print "No samples"
        return

    print "Results: {correct} out of {total} words correct ({percent}%)".format(
        total=total_count, correct=correct_count,
        percent=(correct_count * 100.0 / total_count))


def get_corpora():
    path = os.path.expanduser('~/nltk_data/corpora/wordnet/index.noun')
    with open(path) as f:
        wordlines = (wl for wl in f.readlines() if not wl.startswith(' '))
        words = [wl.split()[0] for wl in wordlines]
    return [w for w in words if not '_' in w]


def sample_words(count, corpora=get_corpora()):
    singulars = random.sample(corpora, count)
    plurals = map(pluralize, singulars)
    return zip(singulars, plurals)


# Pluralization

def pluralize(singular):
    """Returns a plural form of given English noun,
    or more specifically, an attempt at something
    that can sometimes pass as a plural form... maybe.
    """
    plural = None

    if not plural:
        for suffix in ("ff", "fe", "f"):
            if singular.endswith(suffix):
                plural = singular[:-len(suffix)] + "ves"
                break
    if not plural:
        for suffix in ("s", "sh", "x", "z"):
            if singular.endswith(suffix):
                plural = singular + "es"
                break
    if not plural:
        if len(singular) < 2:
            plural = singular + "'s"
        elif singular.endswith("y") and singular[-2] not in "aeiouy":
            plural = singular[:-1] + "ies"

    if not plural:
        plural = singular + "s"
    return plural


if __name__ == '__main__':
    main()