text_download.py

import requests
from collections import Counter, defaultdict

class TextSearch:
    def __init__(self, url):
        self.url = url
        self.word_list = [str(v).lower() for v in self.get_text().split()]
        self.word_lenght = len(self.word_list)
        self.word_count = Counter(self.word_list)
        self.count_word = defaultdict(list)

        for k,v in self.word_count.items():
            self.count_word[v].append(k)

    def get_text(self):
        resp = requests.get(self.url)
        resp.raise_for_status()
        return resp.content

    def most_common(self, number):
        return self.word_count.most_common(number)

    def total_number_words(self):
        return len(self.word_list)

    def unique_word_count(self):
        return len(set(self.word_list))

    def words_that_appear_n_times(self, number):
        return self.count_word[number]

def main():
    url = 'http://pastebin.com/raw/xkTYv7nf'
    words = TextSearch(url)
    print(words.total_number_words())
    print(words.unique_word_count())
    print(words.most_common(5))
    print(words.words_that_appear_n_times(1))

if __name__ == '__main__':
    import sys
    sys.exit(int(main() or 0))