What is the difference between (while queue) and (while not queue.empty()) in Python3

Question

I found the difference between while queue and while not queue.empty() in python3

I thought these are the same, but it wasn't.

when I used

While queue : -> after I used all items in the queue, It just stopped. (No errors)

On the other hand, when I used

While not (queue.empty()): -> it worked as what I thought.

Is there any difference? Or there was something I did wrong?

Thank you!

Answer 1

while queue: will keep looping forever since it's only checking that queue object isn't None. It doesn't care whether it's empty or not, just that the object exists.

For example:

from queue import SimpleQueue

q = SimpleQueue()

while q:
    print ("Queue empty? ", q.empty())

The above script will print "Queue empty? True" infinitely.

Answer 2

You can also do like:

from queue import Queue

q = Queue(maxsize = <maxsize as per your concern>)

while not q.empty():
   print("Queue empty: ", q.empty())
   q.get() #to avoid infinite loop

As per your question, the same followed for me and this was the way I cleared it out so clearly they both are different.