如何创建两个可以相互监视的对象？

Question

我的目标是创建两个交互的对象，特别是创建数据并将其附加到列表的另一个对象，以及可以检查该列表并输出数据的另一个对象。

基于另一个stackoverflow问题，有人建议创建第三个对象来存储数据，并使用前者启动前两个对象。

代码工作是这样的：

class Master: 
    def __init__(self): 
     self.data = [] 
    (some methods for interaction) 

class A: 
    def __init__(self, master_instance): 
     ... 
     self.master_instance = master_instance 
     (call method that randomly generates data and adds it to the master_instance data 
     , and run this for a while (essentially as long as I want this process to continue)) 
    def my_a_method(self): 
     ... 

class B: 
    def __init__(self, master_instance): 
     ... 
     self.master_instance = master_instance 
     (call method that monitors master_instance to see if object A has added any data 
     to it, and spit it out. Like above, run this for as long as I want the process 
     to continue) 
    def my_b_method(self): 
     ... 

master = Master() 
a = A(master) 
b = B(master) 

那么理想，无论是在同一时间运行的过程中。然而，最终发生的是第一个对象被创建，发出所有数据，然后第二个对象运行，而不是同时运行。它的工作原理是它们可以共享数据，但它们在同时运行的意义上不起作用。

（这是一本书的练习，从班章，但他们并没有真正讨论如何做到这一点做）

Answer 1

import multiprocessing as mp 

queue = mp.Queue() 

def adder(q): # for the sake of this example, let's say we want to add squares of all numbers to the queue 
    i = 0 
    while i < 100: 
     q.put(i**2) 
     i += 1 
    q.put(None) 

def monitor(q): # monitor the queue and do stuff with the data therein 
    for e in iter(q.get, None): 
     print(e) # for now, let's just print the stuff 


a = mp.Process(target=adder, args=(queue,)) 
b = mp.Process(target=monitor, args=(queue,)) 
a.start() 
b.start() 
a.join() # wait for the process to finish 
b.join() # wait for the process to finish (both processes running simultaneously) 
a.terminate() 
b.terminate()