如何創建兩個可以相互監視的對象？

Question

我的目標是創建兩個交互的對象，特別是創建數據並將其附加到列表的另一個對象，以及可以檢查該列表並輸出數據的另一個對象。

基於另一個stackoverflow問題，有人建議創建第三個對象來存儲數據，並使用前者啓動前兩個對象。

代碼工作是這樣的：

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) 

那麼理想，無論是在同一時間運行的過程中。然而，最終發生的是第一個對象被創建，發出所有數據，然後第二個對象運行，而不是同時運行。它的工作原理是它們可以共享數據，但它們在同時運行的意義上不起作用。

（這是一本書的練習，從班章，但他們並沒有真正討論如何做到這一點做）

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()