Python multiprocessing Pool apply_async example

gistfile1.txt

#!/usr/bin/env python3

# do an action in parallel across multiple threads in Python
# example: get the average of lists of numbers

# references;
# https://stackoverflow.com/questions/8533318/multiprocessing-pool-when-to-use-apply-apply-async-or-map
# https://e2eml.school/multiprocessing.html
# https://docs.python.org/3.7/library/multiprocessing.html#multiprocessing.pool.Pool.apply_async

from multiprocessing import Pool
from typing import List, Tuple

data = {
    1: [1,2,3],
    2: [3,4,5],
    3: [4,5,6],
    4: [5,6,7],
    5: [6,7,8],
    6: [7,8,9],
    7: [8,9,10],
    8: [10,11,12]
}

def avg(i: int, data: List[int]) -> Tuple[int, float]:
    print("running ", i)
    a = sum(data) / len(data)
    return(i, a)

pool = Pool(4) # run 4 instances in parallel
results = [] # empty list to hold result objects
for i in data:
    print("submitting ", i)
    result = pool.apply_async(avg, (i, data[i]))
    results.append(result)

final = {}

for result in results:
    i, a = result.get() # runs the function and gets the results
    final[i] = a

print("final: ", final)