How to obtain the results from a pool of threads in python?

Python actually has a built-in thread pool you can use, its just not well documented:

from multiprocessing.pool import ThreadPooldef foo(word, number):    print (word * number)    r[(word,number)] = number    return numberwords = ['hello', 'world', 'test', 'word', 'another test']numbers = [1,2,3,4,5]pool = ThreadPool(5)results = []for i in range(0, len(words)):    results.append(pool.apply_async(foo, args=(words[i], numbers[i])))pool.close()pool.join()results = [r.get() for r in results]print results

Or (using map instead of apply_async):

from multiprocessing.pool import ThreadPooldef foo(word, number):    print word*number    return numberdef starfoo(args):    """     We need this because map only supports calling functions with one arg.     We need to pass two args, so we use this little wrapper function to    expand a zipped list of all our arguments.    """        return foo(*args)words = ['hello', 'world', 'test', 'word', 'another test']numbers = [1,2,3,4,5]pool = ThreadPool(5)# We need to zip together the two lists because map only supports calling functions# with one argument. In Python 3.3+, you can use starmap instead.results = pool.map(starfoo, zip(words, numbers))print resultspool.close()pool.join()