Python script to generate words from letters and two letter combination

Question

I\'m looking to write a short script that will allow me to generate all possible letter combinations with the parameters I set.

For example:

_ _ b _ a

P

Answer 1

I would approach this as follows, using itertools.product in a generator function (to avoid building the whole list unless you absolutely have to):

from itertools import product

def words(definition):
    for t in product(*definition):
        yield "".join(t)

The only trick is providing the definition in an appropriate format; it must be a list of iterables, each of which provides the options for each "letter". This is easy where each option for a letter is a single character:

>>> list(words(["f", "o", "aeiou"]))
['foa', 'foe', 'foi', 'foo', 'fou']

But with your multiple-character letters you will need to supply a list or tuple:

>>> list(words([['ph', 'sd', 'nn', 'mm', 'gh'], 
                ['a', 'e', 'i', 'o', 'u', 'y', 'rc'], 
                'b', 
                ['a', 'e', 'i', 'o', 'u', 'y', 'rc'], 
                'a']))
['phabaa', 'phabea', 'phabia', ..., 'ghrcbya', 'ghrcbrca']

Note that in Python 3.3 onwards, this can be done in a single line with yield from:

def words(definition):
    yield from map("".join, product(*definition))