Solve The Washington Post's Keyword game

wapo-keyword.py

#!/usr/bin/python3
#
# wapo-keyword.py
#
# Program to solve The Washington Post's Keyword game.
# https://www.washingtonpost.com/games/keyword
#
# Usage: Enter the words on the command line, using a period for the 
# missing letters.
#
# Example: keyword.py .nsist ba. pro.ane st.ut sto.e clai.

import sys
import re

# Although you can use /usr/dict/words as a list of possible words,
# it is missing many words and forms. I created my own custom wordlist
# based on /usr/share/dict/words and the 2019 Scrabble dictionary, with all
# characters converted to lowercase, Unicode characters converted to ASCII,
# and proper nouns and possessive's removed.
# wordlist = "/usr/share/dict/words"
wordlist = "wordlist.txt"

classes = "^" # Anchor the pattern to the beginning of the line
# Build the character classes for each input word
for word in sys.argv[1:]:
    # Get the position of the missing letter
    pos = word.index('.')
    pattern = re.compile("^"+word+"$")

    # Find all words that match the pattern
    results = []
    with open(wordlist,'r') as dict:
        for word in dict:
            result = pattern.findall(word)
            if result:
                results.extend(result)

    # Make a character class of all the possible missing letters.
    charclass = "["
    for str in results:
        charclass += str[pos]
    charclass += "]"

    classes += charclass
classes += "$" # Anchor the pattern to the end of the line

# Use the constructed character classes to search for the answer
# in the wordlist.
results = []
pattern = re.compile(classes)
with open(wordlist,'r') as dict:
    for word in dict:
        result = pattern.findall(word)
        if result:
            results.extend(result)

# Display the solution
print(results)