"""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
"""
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)
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
"""
t = []
for v in d.values():
if len(v) > 1:
t.append((len(v), v))
t.sort()
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)
