Word combination finder

Readme.md

Started with https://gist.github.com/gubatron/65a153478149118908c6

• Made it work (original was probably Python 2?)
• Significantly tidied the code
• Performance: Removed redundant sorting
• Performance: Made input permutations unique so identical combinations weren't tried more than once

Still very slow for inputs 9+ letters long. Roughly exponential - takes around 1s for an 8 letter word, 10-11x longer for each additional letter.

word_challenge.py

import os
from itertools import groupby, permutations
from time import time

def clean_word(word):
    return word.strip().lower()

def load_words():
    words = {}

    f = open('words.txt')
    f.seek(0, os.SEEK_END)
    end = f.tell()
    f.seek(0)

    loaded = 0
    while f.tell() < end:
        word = clean_word(f.readline())
        words[word] = ''
        loaded += 1
        if loaded % 100 == 0:
            print("\r%d    words loaded" % loaded, end = '')

    print("\rFinished loading dictionary - %d words" % loaded)
    return words

def find_words(letters, words):
    letters = clean_word(letters)
    MIN_WORD_LENGTH = 3
    key_func = lambda x: ''.join(x)
    return [
        perm for comb_size in range(MIN_WORD_LENGTH, len(letters) + 1)
        for perm in [k for k, _ in groupby(sorted(permutations(letters, comb_size), key=key_func), key=key_func)]
        if perm in words
    ]

words = load_words()

while True:
    letters = input("ENTER LETTERS TO FIND WORDS (Press Ctrl-D to end): ")
    print("Generating valid combinations...")

    t0 = time()
    found = find_words(letters, words)
    t1 = time()
    total_time = t1 - t0

    WORDS_PER_LINE = 4
    word_count = 0
    for f in found:
        print(f, "  ", end = '')
        word_count += 1

        if word_count == WORDS_PER_LINE:
            print("")
            word_count = 0

    print("")
    print("Finished in %s s" % total_time)