4-top_3_words.py

# https://www.codewars.com/kata/51e056fe544cf36c410000fb/train/python

from collections import Counter
from re import split, sub


def top_3_words(text):
    words = map(lambda e: sub("'+", "'", e), split("[^a-z']", text.lower()))
    counts = Counter(filter(lambda e: e not in ['', "'"], words))
    return [e[0] for e in counts.most_common(3)]


print(top_3_words(
    "a a a  b  c c  d d d d  e e e e e"), ["e", "d", "a"])
print(top_3_words(
    "e e e e DDD ddd DdD: ddd ddd aa aA Aa, bb cc cC e e e"), ["e", "ddd", "aa"])
print(top_3_words(
    "e' e' e' e' DDD ddd DdD: ddd ddd aa aA Aa, bb cc cC e' e' e'"), ["e'", "ddd", "aa"])
print(top_3_words("  //wont won't won't "), ["won't", "wont"])
print(top_3_words("  , e   .. "), ["e"])
print(top_3_words("  ...  "), [])
print(top_3_words("  '  "), [])
print(top_3_words("  '''  "), [])
print(top_3_words("""In a village of La Mancha, the name of which I have no desire to call to
mind, there lived not long since one of those gentlemen that keep a lance
in the lance-rack, an old buckler, a lean hack, and a greyhound for
coursing. An olla of rather more beef than mutton, a salad on most
nights, scraps on Saturdays, lentils on Fridays, and a pigeon or so extra
on Sundays, made away with three-quarters of his income."""), ["a", "of", "on"])