为 python 中的多处理函数获取 return 值

Question

我有两个并行运行的函数，每个函数 returns 一个值。我需要等待这两个函数完成，然后处理它们的 returns 。我如何才能在 python 中实现这一点。假设

def fun1():
   #do some calculation#
   return val1

def fun2():
   #do some calculation#
   return val2

我想让fun1和fun2并行运行然后需要计算

valsum = val1+val2

Answer 1

使用 concurrent.futures:

from concurrent.futures import ProcessPoolExecutor as Executor
#from concurrent.futures import ThreadPoolExecutor as Executor  # to use threads
with Executor() as executor:
    future1 = executor.submit(fun1, arg1, arg2, ...)
    future2 = executor.submit(fun2, arg1, arg2, ...)
    val1, val2 = future1.result(), future2.result()
    valsum = val1 + val2

concurrent.futures.Executor.submit schedules the function to be executed, and returns a concurrent.futures.Future 对象。

concurrent.futures.Future.resultreturn 由函数编辑的 return 值 return。

使用multiprocessing.pool:

from multiprocessing.pool import Pool
#from multiprocessing.pool import ThreadPool as Pool  # to use threads
with multiprocessing.pool.Pool() as pool:
    result1 = pool.apply_async(fun1, (arg1, arg2, ...))
    result2 = pool.apply_async(fun2, (arg1, arg2, ...))
    val1, val2 = result1.get(), result2.get()
    valsum = val1 + val2

multiprocessing.pool.Pool.apply_async return 一个 AsyncResult 对象，并且 AsyncResult.get 将 return 函数的 return 值一旦完成并且结果到达。

为 python 中的多处理函数获取 return 值

Get return value for multi-processing functions in python

python

python-multithreading

python-multiprocessing