Using Queue in python

Question

I'm trying to run the following in Eclipse (using PyDev) and I keep getting error :

q = queue.Queue(maxsize=0) NameError: global name 'queue' is not defined

I've checked the documentations and appears that is how its supposed to be placed. Am I missing something here? Is it how PyDev works? or missing something in the code? Thanks for all help.

from queue import *  def worker():     while True:         item = q.get()         do_work(item)         q.task_done()  def main():      q = queue.Queue(maxsize=0)     for i in range(num_worker_threads):          t = Thread(target=worker)          t.daemon = True          t.start()      for item in source():         q.put(item)      q.join()       # block until all tasks are done  main() 

Using: Eclipse SDK

Version: 3.8.1 Build id: M20120914-1540

and Python 3.3

Answer 1

You do

from queue import * 

This imports all the classes from the queue module already. Change that line to

q = Queue(maxsize=0) 

CAREFUL: "Wildcard imports (from import *) should be avoided, as they make it unclear which names are present in the namespace, confusing both readers and many automated tools". (Python PEP-8)

As an alternative, one could use:

from queue import Queue  q = Queue(maxsize=0) 

Answer 2

That's because you're using : from queue import *

and then you're trying to use :

queue.Queue(maxsize=0)  

remove the queue part, because from queue import * imports all the attributes to the current namespace. :

Queue(maxsize=0)  

or use import queue instead of from queue import *.