Why does this queue empty out, while I operate on a copy of it?

Question

I have a function (Python 3):

import queue

q = queue.Queue()

q.put(1)
q.put(2)
q.put(3)

def printqueue(u):
    while not u.empty():
        print(u.get())

printqueue(q)

print(q.empty())

Why is q empty at the end while I operated on u? Is there a way to fix this?

Answer 1

Because you do not operate on a copy of it, but instead the exact same object.

You can easily check this with the built-in id function:

import queue

q = queue.Queue()

def printqueue(u):
    print(id(u))

print(id(q))
printqueue(q)

Output:

140230517913872
140230517913872