在類線程之間發送消息Python

Question

有沒有人知道如何在不使用全局變量的情況下將代碼中的變量（或變量）從threadOne發送到threadTwo？如果不是，我將如何操作一個全局變量？只需在兩個類之前定義它並在運行函數中使用全局定義？

import threading 

print "Press Escape to Quit" 

class threadOne(threading.Thread): #I don't understand this or the next line 
    def run(self): 
     setup() 

    def setup(): 
     print 'hello world - this is threadOne' 


class threadTwo(threading.Thread): 
    def run(self): 
     print 'ran' 

threadOne().start() 
threadTwo().start() 

感謝

Answer 1

您可以使用queues在一個線程安全的方式發送線程之間的消息。

def worker(): 
    while True: 
     item = q.get() 
     do_work(item) 
     q.task_done() 

q = Queue() 
for i in range(num_worker_threads): 
    t = Thread(target=worker) 
    t.daemon = True 
    t.start() 

for item in source(): 
    q.put(item) 

q.join()  # block until all tasks are done 

Answer 2

在這裏，使用Lock。

import threading 

print "Press Escape to Quit" 

# Global variable 
data = None 

class threadOne(threading.Thread): #I don't understand this or the next line 
    def run(self): 
     self.setup() 

    def setup(self): 
     global data 
     print 'hello world - this is threadOne' 

     with lock: 
      print "Thread one has lock" 
      data = "Some value" 


class threadTwo(threading.Thread): 
    def run(self): 
     global data 
     print 'ran' 
     print "Waiting" 

     with lock: 
      print "Thread two has lock" 
      print data 

lock = threading.Lock() 

threadOne().start() 
threadTwo().start() 

使用全局變量data。

第一個線程獲取鎖並寫入變量。

第二個線程等待數據並打印它。

更新

如果有兩個以上的線程這​​就需要消息被傳來傳去，最好是使用threading.Condition。