Python Codewars problems

Most frequently used words in a text

4 KYU

Write a function that, given a string of text (possibly with punctuation and line-breaks), returns an array of the top-3 most occurring words, in descending order of the number of occurrences.

Assumptions:

A word is a string of letters (A to Z) optionally containing one or more apostrophes (') in ASCII.

Apostrophes can appear at the start, middle or end of a word ('abc, abc', 'abc', ab'c are all valid) Any other characters (e.g. #, \, / , . ...) are not part of a word and should be treated as whitespace.

Matches should be case-insensitive, and the words in the result should be lowercased.

Ties may be broken arbitrarily.

If a text contains fewer than three unique words, then either the top-2 or top-1 words should be returned, or an empty array if a text contains no words.

Examples:

"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"]


"e e e e DDD ddd DdD: ddd ddd aa aA Aa, bb cc cC e e e"

--> ["e", "ddd", "aa"]


"  //wont won't won't"

--> ["won't", "wont"]

Bonus points (not really, but just for fun):

• Avoid creating an array whose memory footprint is roughly as big as the input text.
• Avoid sorting the entire array of unique words.

# Marquins solution
# NB fails on situation with ties

from collections import Counter

def top_3_words(text: str) -> list:

    text_copy = str(text)

    # remove all punctuation except apostrophes
    remove_punctuation = [x for x in "#/\!@$%^&*().,"]

    for punctuation in remove_punctuation:
        text_copy = text_copy.replace(punctuation, '')

    # split string based on spaces
    text_list = text_copy.split(" ")

    # filter out empty strings and strings that contain only apostrophes
    to_filter = ['', "'", "''", "'''"]
    text_list = [x for x in text_list if x not in to_filter]

    # sort list
    text_list.sort()
    print(text_list)

    # count occurances and sort
    my_counter_object = Counter(text_list).most_common(3)

    print(my_counter_object)
    #
    to_return = [x[0] for x in my_counter_object]

    print(to_return)

    return to_return