anagram.py

#!/usr/bin/python3
from collections import defaultdict

def words(words_file):
    """Return one word at a time from a potentially very large list of words."""
    with open(words_file, 'r') as f:
        for line in f:
            # give back one word at a time, with no whitespace, and converted to
            # lowercase.
            yield line.casefold().strip()


def anagram(word_generator):
    """Words are anagrams if you get the same string if you sort their characters alphabetically.
    """
    anagrams = defaultdict(list)
    for word in iter(word_generator()):
        anagrams[''.join(sorted(word))].append(word)

    # return the lists that have more than one element -- ie an anagram was found.
    return [v for v in anagrams.values() if len(v)>1]

for anagram in anagram(words('words.txt')):
    print(','.join(anagram))
print(f'{len(anagrams)} anagrams found')