Python - How to make crossword solver faster
<p>I have the following function that is part of a crossword solver:</p>

<pre><code>def CrosswordPossibleWords(p_words, p_cw_words):
    """For each word found in the crossword, find the possible words and keep track of the one with the minimum possible words.

    Keyword arguments:
    p_words    -- The dictionary words.
    p_cw_words -- The crossword word attributes.
    """
    l_min = 999999999
    l_min_index = -1
    l_index = 0
    l_choices = []
    for l_cw_word in p_cw_words:
        if l_cw_word[2] &gt;= l_min_length and '-' in l_cw_word[4]:
            pattern = re.compile('^' + l_cw_word[4].replace('.', '%').replace('-', '.').upper() + '$', re.UNICODE)
            l_choice = []
            for l_word in [w for w in p_words if len(w) == len(l_cw_word[4])]:
                if re.match(pattern, l_word):
                    l_choice.append(l_word)
            l_choices.append(l_choice)
            if len(l_choice) &lt; l_min:
                l_min_index = l_index
                l_min = len(l_choice)
        else:
            l_choices.append([])
        l_index = l_index + 1
    return (l_choices, l_min_index)
</code></pre>

<p>The crossword words are of the form:</p>

<pre><code>[row, col, length, direction, word]
</code></pre>

<p>I have a <code>'.'</code> in a word if I can't solve that word and a <code>'-'</code> if I don't know that letter.</p>

<p>How can I make this code faster? It currently takes about 2.5 seconds to run. Was thinking of using numpy strings; since apparently numpy is 10 times faster, but I don't know anything about numpy and don't know whether I would be able to use all the current string functions with it.</p>

<p>Any ideas?</p>
