"""This module contains a code example related to Think Python, 2nd Edition by Allen Downey http://thinkpython2.com Copyright 2015 Allen Downey License: http://creativecommons.org/licenses/by/4.0/ """ from __future__ import print_function, division def signature(s): """Returns the signature of this string. Signature is a string that contains all of the letters in order. s: string """ # TODO: rewrite using sorted() t = list(s) t.sort() t = ''.join(t) return t def all_anagrams(filename): """Finds all anagrams in a list of words. filename: string filename of the word list Returns: a map from each word to a list of its anagrams. """ d = {} for line in open(filename): word = line.strip().lower() t = signature(word) # TODO: rewrite using defaultdict if t not in d: d[t] = [word] else: d[t].append(word) return d def print_anagram_sets(d): """Prints the anagram sets in d. d: map from words to list of their anagrams """ for v in d.values(): if len(v) > 1: print(len(v), v) def print_anagram_sets_in_order(d): """Prints the anagram sets in d in decreasing order of size. d: map from words to list of their anagrams """ # make a list of (length, word pairs) t = [] for v in d.values(): if len(v) > 1: t.append((len(v), v)) # sort in ascending order of length t.sort() # print the sorted list for x in t: print(x) def filter_length(d, n): """Select only the words in d that have n letters. d: map from word to list of anagrams n: integer number of letters returns: new map from word to list of anagrams """ res = {} for word, anagrams in d.items(): if len(word) == n: res[word] = anagrams return res if __name__ == '__main__': anagram_map = all_anagrams('words.txt') print_anagram_sets_in_order(anagram_map) eight_letters = filter_length(anagram_map, 8) print_anagram_sets_in_order(eight_letters)