multiprocessing_pool_apply_async.py

from time import time, sleep
from random import randrange
from multiprocessing import Pool, cpu_count

numbers = range(1, 100)
sleep_sec = randrange(1, 2)

return_r = []


def basic_func(x):
    sleep(sleep_sec)
    if x == 0:
        return 'zero'
    elif x % 2 == 0:
        return 'even'
    else:
        return 'odd'


def result(x):
    return_r.append(x)


if __name__ == '__main__':
    p = Pool(processes=2)
    start = int(round(time() * 1000))
    for num in numbers:
        p.apply_async(basic_func, [num], callback=result)
    p.close()
    p.join()
    print("Complete")
    end = int(round(time() * 1000)) - start
    print('total time (ms) =  %s' % end)
    print(return_r)
    print(len(return_r))