queue.Queue and collections.deque serve different purposes. queue.Queue is intended for allowing different threads to communicate using queued messages/data, whereas collections.deque is simply intended as a data structure. That's why queue.Queue has methods like put_nowait(), get_nowait(), and join(), whereas collections.deque doesn't. queue.Queue isn't intended to be used as a collection, which is why it lacks the likes of the in operator.
It boils down to this: if you have multiple threads and you want them to be able to communicate without the need for locks, you're looking for queue.Queue; if you just want a queue or a double-ended queue as a datastructure, use collections.deque.
Finally, accessing and manipulating the internal deque of a queue.Queue is playing with fire - you really don't want to be doing that.
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queue.Queue and collections.deque serve different purposes. queue.Queue is intended for allowing different threads to communicate using queued messages/data, whereas collections.deque is simply intended as a data structure. That's why queue.Queue has methods like put_nowait(), get_nowait(), and join(), whereas collections.deque doesn't. queue.Queue isn't intended to be used as a collection, which is why it lacks the likes of the in operator.
It boils down to this: if you have multiple threads and you want them to be able to communicate without the need for locks, you're looking for queue.Queue; if you just want a queue or a double-ended queue as a datastructure, use collections.deque.
Finally, accessing and manipulating the internal deque of a queue.Queue is playing with fire - you really don't want to be doing that.
If all you're looking for is a thread-safe way to transfer objects between threads, then both would work (both for FIFO and LIFO). For FIFO:
Queue.put()andQueue.get()are thread-safe- Deques support thread-safe, memory efficient appends and pops from either side of the deque with approximately the same O(1) performance in either direction.
Note:
- Other operations on
dequemight not be thread safe, I'm not sure. dequedoes not block onpop()orpopleft()so you can't base your consumer thread flow on blocking till a new item arrives.
However, it seems that deque has a significant efficiency advantage. Here are some benchmark results in seconds using CPython 2.7.3 for inserting and removing 100k items
deque 0.0747888759791
Queue 1.60079066852
Here's the benchmark code:
import time
import Queue
import collections
q = collections.deque()
t0 = time.clock()
for i in xrange(100000):
q.append(1)
for i in xrange(100000):
q.popleft()
print 'deque', time.clock() - t0
q = Queue.Queue(200000)
t0 = time.clock()
for i in xrange(100000):
q.put(1)
for i in xrange(100000):
q.get()
print 'Queue', time.clock() - t0