extracting a heapq in a for loop - there must be more elegant solution
Helmut Jarausch
jarausch at igpm.rwth-aachen.de
Wed Dec 4 04:44:49 EST 2013
On Wed, 04 Dec 2013 08:13:03 +1100, Cameron Simpson wrote:
> On 03Dec2013 12:18, Helmut Jarausch <jarausch at igpm.rwth-aachen.de> wrote:
>> I'd like to extracted elements from a heapq in a for loop.
>> I feel my solution below is much too complicated.
>> How to do it more elegantly?
>
> I can't believe nobody has mentioned PriorityQueue.
>
> A PriorityQueue (from the queue module in python 3 and the Queue
> module in python 2) is essentially just a regular Queue using a
> heapq for the storage.
>
> Example (untested):
>
> from Queue import PriorityQueue
>
> PQ = PriorityQueue()
> for item in [1,2,3,7,6,5,9,4]:
> PQ.put(item)
>
> while not PQ.empty():
> item = PQ.get()
> ... do stuff with item ...
>
> I iterate over Queues so often that I have a personal class called
> a QueueIterator which is a wrapper for a Queue or PriorityQueue
> which is iterable, and an IterablePriorityQueue factory function.
> Example:
>
> from cs.queues import IterablePriorityQueue
>
> IPQ = IterablePriorityQueue()
> for item in [1,2,3,7,6,5,9,4]:
> IPQ.put(item)
>
> for item in IPQ:
> ... do stuff with item ...
>
> Cheers,
Many thanks!
I think you QueueIterator would be a nice addition to Python's library.
Helmut
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