wordcount.py

import re
from hash_map import HashMap

"""
This is the regular expression used to capture words. It could probably be endlessly
tweaked to catch more words, but this provides a standard we can test against, so don't
modify it for your assignment submission.
"""
rgx = re.compile("(\w[\w']*\w|\w)")


def hash_function_2(key):
    """
    This is a hash function that can be used for the hashmap.
    """

    var_hash = 0
    var_index = 0
    for i in key:
        var_hash = var_hash + (var_index + 1) * ord(i)
        var_index = var_index + 1
    return var_hash


def top_words(source, number):
    """
    Takes a plain text file and counts the number of occurrences of case insensitive words.
    Returns the top `number` of words in a list of tuples of the form (word, count).

    Args:
        source: the file name containing the text
        number: the number of top results to return (e.g. 5 would return the 5 most common words)
    Returns:
        A list of tuples of the form (word, count), sorted by most common word. (e.g. [("a", 23), ("the", 20), ("it", 10)])
    """

    keys = set()

    ht = HashMap(2500, hash_function_2)

    # This block of code will read a file one word as a time and
    # put the word in `w`. It should be left as starter code.
    with open(source) as f:
        for line in f:
            words = rgx.findall(line)
            for w in words:

                # WRITTEN
                w = w.lower()
                if ht.contains_key(w):
                    assert(w in keys)
                    ht.put(w, ht.get(w))
                else:
                    keys.add(w)
                    ht.put(w, 1)

    sorted_words = sorted(keys, reverse=True,
                          key= lambda word: ht.get(word))
    high_scores = sorted_words[:number]

print(top_words("alice.txt", 10))  # COMMENT THIS OUT WHEN SUBMITTING TO GRADESCOPE