Clear all items from a Queue in Python

Borislav Hadzhiev

Thu Jun 16 2022·1 min read

Clear all items from a Queue in Python #

To clear all items from a queue in Python:

Use the queue attribute on the queue to get a deque object.
Call the clear() method on the deque object, e.g. q.queue.clear().
The clear method will remove all elements from the queue.

main.py

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import queue

q = queue.Queue()

for item in range(10):
    q.put(item)

print(q.queue)  # 👉️ deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

q.queue.clear()

print(q.queue)  # 👉️ deque([])

The queue attribute points to a deque object, and deque objects implement a clear method.

The clear() method removes all elements from the deque and leaves it with a length of 0.

If you need to make the operation thread safe, use a mutex lock.

main.py

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import queue

q = queue.Queue()

for item in range(10):
    q.put(item)

print(q.queue)  # 👉️ deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

# 👇️ use mutex lock
with q.mutex:
    q.queue.clear()

print(q.queue)  # 👉️ deque([])

You can use a mutex lock if your code runs in a multithreaded environment.

An alternative is to simply create a new queue and delete the old one.

main.py

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import queue

q = queue.Queue()

for item in range(10):
    q.put(item)

del q  # 👈️ delete old queue


new_q = queue.Queue()

print(new_q.queue)  # 👉️ deque([])

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