python Pool with worker Processes

Question

I am trying to use a worker Pool in python using Process objects. Each worker (a Process) does some initialization (takes a non-trivial amount of time), gets passed a serie

Answer 1

Since python 3.3 you can use starmap, also for using multiple arguments AND getting back the results in a very simplistic syntax:

import multiprocessing

nb_cores = multiprocessing.cpu_count()

def caps(nb, letter):
    print('Exec nb:', nb)
    return letter.upper()

if __name__ == '__main__':

    multiprocessing.freeze_support() # for Windows, also requires to be in the statement: if __name__ == '__main__'

    input_data = ['a','b','c','d','e','f','g','h']
    input_order = [1,2,3,4,5,6,7,8,9]

    with multiprocessing.Pool(processes=nb_cores) as pool: # auto closing workers
        results = pool.starmap(caps, zip(input_order, input_data))

    print(results)