lesson04_submit_many_tasks.py

# SuperFastPython.com
# example issuing many asynchronous tasks systematically
from random import random
from time import sleep
from concurrent.futures import ThreadPoolExecutor

# custom function to be executed in a worker thread
def task(number):
 # generate a random value between 0 and 1
 value = random()
 # report a message
 print(f'Task generated {value}')
 # block for a moment to simulate work
 sleep(value)
 # return a new value
 return number + value

# protect the entry point
if __name__ == '__main__':
 # create the thread pool
 with ThreadPoolExecutor() as ex:
 # issue many asynchronous tasks systematically
 futures = [ex.submit(task, i) for i in range(5)]
 # enumerate futures and report results
 for future in futures:
 print(future.result())