本文介绍了Python 可迭代队列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我需要知道队列何时关闭并且不会有更多项目，以便我可以结束迭代.
I need to know when a Queue is closed and wont have more items so I can end the iteration.
我通过在队列中放置一个哨兵来做到这一点:
I did it by putting a sentinel in the queue:
from Queue import Queue
class IterableQueue(Queue):
_sentinel = object()
def __iter__(self):
return self
def close(self):
self.put(self._sentinel)
def next(self):
item = self.get()
if item is self._sentinel:
raise StopIteration
else:
return item
鉴于这是队列的一种非常常见的用途，难道没有任何内置实现吗?
Given that this is a very common use for a queue, isn't there any builtin implementation?
推荐答案
sentinel 是生产者发送没有更多队列任务即将到来的消息的合理方式.
A sentinel is a reasonable way for a producer to send a message that no more queue tasks are forthcoming.
FWIW，您的代码可以使用 iter():
FWIW, your code can be simplified quite a bit with the two argument form of iter():
from Queue import Queue
class IterableQueue(Queue):
_sentinel = object()
def __iter__(self):
return iter(self.get, self._sentinel)
def close(self):
self.put(self._sentinel)
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