Finding statistically best guesses for the Wordle game

best_wordle_guess.py

#!/usr/bin/env python3
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# MIT License
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# Copyright (c) 2021 Marcel Bollmann
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"""Usage: best_wordle_guess.py WORDLIST [options]

Finds the statistically best guesses for the Wordle game
<https://www.powerlanguage.co.uk/wordle/>, using a list of English words and a
simple frequency-counting approach *by position within the word.*

Arguments:
  WORDLIST                 Lexicon file with one word per line.

Options:
  --after GUESS            Find a word that has no letters in common with GUESS.
  -h, --help               Display this helpful text.
"""

from collections import Counter
from docopt import docopt
import itertools as it
import os

from rich.console import Console
from rich.table import Table
console = Console()


def load_wordlist(filename):
    wordlist = []
    with open(filename, "r") as f:
        for line in f:
            word = line.strip()
            if len(word) != 5:
                continue
            wordlist.append(word)
    wordlist = set(wordlist)
    console.print(f"Found {len(wordlist)} words of length 5.")
    return wordlist


def find_common_letters(wordlist, MAX=5):
    letters = [None] * 5
    for pos in range(5):
        c = Counter(word[pos] for word in wordlist)
        letters[pos] = c.most_common(MAX)

    table = Table(title="Most frequent letters by position")
    for pos in range(5):
        table.add_column(f"Pos {pos+1}", justify="right")
        table.add_column(f"Freq", justify="right")
    for rank in range(MAX):
        row = []
        for pos in range(5):
            row.extend(str(x) for x in letters[pos][rank])
        table.add_row(*row)

    console.print("")
    console.print(table)
    return letters


def find_best_guess(wordlist, letters, after=None):
    if after is None:
        console.print(f"\n[bold blue]Best initial guesses:[/]")
    else:
        console.print(f"\n[bold blue]Best guesses after '[green]{after}[/]':[/]")

    guesses = Counter()
    for candidate in it.product(*letters):
        word = "".join([c[0] for c in candidate])
        if len(set(word)) != 5:
            # contains the same letter more than once
            continue
        if word not in wordlist:
            # not a legal word
            continue
        if after is not None and len(set(word + after)) < len(word + after):
            continue

        # sum up the frequencies so we can later sort by best accumulated frequency
        guesses[word] = sum(c[1] for c in candidate)

    for (word, score) in guesses.most_common(10):
        console.print(f"{word}   {score:6d}")


if __name__ == "__main__":
    args = docopt(__doc__)
    wordlist = args["WORDLIST"]
    if not os.path.exists(wordlist):
        raise FileNotFoundError(f"File not found: {wordlist}")

    wordlist = load_wordlist(wordlist)
    letters = find_common_letters(wordlist, MAX=10)
    find_best_guess(wordlist, letters, after=args["--after"])

Requirements: docopt and rich.

Using words-alpha.txt from dwyl/english-words as the word list, the best valid* guesses that have no letters in common are:

1. cares
2. monty
3. build

(*the Wordle lexicon appears to be much more restrictive than the linked word list)