CODEWITHSUNDEEP
pythonqueue
Nick Nelson
Nick Nelson

Reputation: 21

Python queue module difficulty

I'm an experienced programmer, but completely new to Python. I've resolved most difficulties, but I can't get the queue module to work. Any help gratefully received. Python 3.2.

Reduced to its basic minimum, here's the issue:

>>>import queue
>>>q = queue.Queue
>>>q.qsize()
Traceback:
...
   q.qsize()
...
TypeError: qsize() takes 1 argument exactly (0 given)

Documentation...

7.8.1. Queue Objects

Queue objects (Queue, LifoQueue, or PriorityQueue) provide the public methods described below.

Queue.qsize()

OK - what argument.... ?

Upvotes: 2

Views: 579

Answers (2)

goofd
goofd

Reputation: 2098

You are simply renaming queue.Queue and not instantiating an object.

Try this

q = queue.Queue()
print q.qsize()

Upvotes: 1

voithos
voithos

Reputation: 70632

You're not initializing an instance, you're just reassigning the class name to q. The "argument" that it's talking about is self, the explicit self-reference that all Python methods need. In other words, it's saying that you're trying to call an instance method with no instance.

>>> q = queue.Queue()
>>> q.qsize()

If you've never seen a Python method definition, it looks something like this:

class Queue(object):
    # Note the explicit 'self' argument
    def qsize(self):
        # ...

Upvotes: 5

Related Questions