words8.py

# What 8 letter word can have a letter taken away, and each time still make another word, until only one letter (and one word) are left?
words_by_length = [set(), set(), set(), set(), set(), set(), set(), set(), set()]
with open('scrabble2019.txt') as f:
    for w in f:
        word = w.strip()
        word_len = len(word)
        if word_len <= 8:
            words_by_length[word_len].add(word)

answers = set()

def find_word(word, history):
    history.append(word)
    if len(word) == 8:
        answers.add(word)
        history.reverse()
        print(history)
        return
    for next_word in words_by_length[len(word)+1]:
        if word in next_word:
            find_word(next_word, history[:])

find_word('A', list())
find_word('I', list())
find_word('O', list())

print(answers,len(answers))