Check if a set of characters is contained in a string?

Question

There is a pool of letters (chosen randomly), and you want to make a word with these letters. I found some codes that can help me with this, but then if the word has for example 2 L's and the pool only 1, I'd like the program to know when this happens.

Answer 1

If I understand this correctly, you will also need a list of all valid words in whichever language you are using.

Assuming you have this, then one strategy for solving this problem could be to generate a key for every word in the dictionary that is a sorted list of the letters in that word. You could then group all words in the dictionary by these keys.

Then the task of finding out if a valid word can be constructed from a given list of random characters would be easy and fast.

Here is a simple implementation of what I am suggesting:

list_of_all_valid_words = ['this', 'pot', 'is', 'not', 'on', 'top']

def make_key(word):
    return "".join(sorted(word))

lookup_dictionary = {}

for word in list_of_all_valid_words:
    key = make_key(word)
    lookup_dictionary[key] = lookup_dictionary.get(key, set()).union(set([word]))

def words_from_chars(s):
    return list(lookup_dictionary.get(make_key(s), set()))

print words_from_chars('xyz')
print words_from_chars('htsi')
print words_from_chars('otp')

Output:

[]
['this']
['pot', 'top']