如何确定 Python 个带有队列的线程是否已完成任务？

Question

这里我有 MazeRunner Class 将 self.boxes 的所有元素放入队列并运行在它们上面线程化，直到所有队列都变空 q.empty().

Here problem is how do i actually identify if my program is done performing threads on all elements which are in queue of self.boxes & return True.

它看起来很有挑战性，因为 our threads 处于 while 循环中，它根据我们定义的 self.boxes 长度和 self.threads 保持变化。我已经尝试将所有线程放入列表中并 t.join 全部。但不是运气。有帮助吗？

import threading,queue,time 

class MazeRunner:
    def __init__(self):
        self.q = queue.Queue()
        self.boxes = [1,2,3,4,5,6,7] ## `7` elements of list
        self.threads = 5

        for i in self.boxes:
            self.q.put(i) ### ADDING Every element of list to queue

        for j in range(self.threads): ### for i in range(5)  threads
            t = threading.Thread(target=self.ProcessQueue)
            t.start() ### Started `5` threads on `7` elements

    def ProcessQueue(self):
        while not self.q.empty():
            each_element = self.q.get()
            self.SleepFunction(each_element)
            self.q.task_done()

    def SleepFunction(self,each_element):
        print("STARTING : ",each_element)
        time.sleep(10)
        print("DONE : ",each_element)

lets_try = MazeRunner()
if lets_try == True:
     print("All Threads Done on Elements")

Answer 1

您需要等到所有线程都完成调用 Thread.join:

HOWTO：

用 class 常量替换您的 self.threads = 5 表达式：
```
THREAD_NUM = 5
```
将附加属性 threads（用于线程列表）放入您的 __init__ 方法中：
```
...
self.threads = []
```

将每个创建的线程放入threads列表：

for j in range(self.THREAD_NUM):
    t = threading.Thread(target=self.ProcessQueue)
    self.threads.append(t)
    t.start()

定义类似check_completed的方法以确保所有线程都被终止（完成）：

....

def check_completed(self):
    for t in self.threads:
        t.join()
    return True

您需要检查的方式"all done"：

m_runner = MazeRunner()
if m_runner.check_completed():
    print("All Threads Done on Elements")

如何确定 Python 个带有队列的线程是否已完成任务？

How to identify if Python Threads with Queue are done with task?

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python-2.7

python-3.x