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Groups > comp.lang.python > #60961

Re: extracting a heapq in a for loop - there must be more elegant solution

Date 2013-12-04 08:13 +1100
From Cameron Simpson <cs@zip.com.au>
Subject Re: extracting a heapq in a for loop - there must be more elegant solution
References <bg60hjF83eoU1@mid.dfncis.de>
Newsgroups comp.lang.python
Message-ID <mailman.3528.1386105197.18130.python-list@python.org> (permalink)

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On 03Dec2013 12:18, Helmut Jarausch <jarausch@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,
-- 
Cameron Simpson <cs@zip.com.au> http://www.cskk.ezoshosting.com/cs/

Those who do not understand Unix are condemned to reinvent it, poorly.
        - Henry Spencer @ U of Toronto Zoology, henry@zoo.toronto.edu

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Thread

extracting a heapq in a for loop - there must be  more elegant solution Helmut Jarausch <jarausch@igpm.rwth-aachen.de> - 2013-12-03 12:18 +0000
  Re: extracting a heapq in a for loop - there must be more elegant solution Peter Otten <__peter__@web.de> - 2013-12-03 13:38 +0100
    Re: extracting a heapq in a for loop - there must be more elegant solution Helmut Jarausch <jarausch@igpm.rwth-aachen.de> - 2013-12-04 09:36 +0000
      Re: extracting a heapq in a for loop - there must be more elegant solution Peter Otten <__peter__@web.de> - 2013-12-04 10:50 +0100
  Re: extracting a heapq in a for loop - there must be  more elegant solution rusi <rustompmody@gmail.com> - 2013-12-03 04:40 -0800
    Re: extracting a heapq in a for loop - there must be  more elegant solution Helmut Jarausch <jarausch@igpm.rwth-aachen.de> - 2013-12-04 09:37 +0000
  Re: extracting a heapq in a for loop - there must be  more elegant solution Duncan Booth <duncan.booth@invalid.invalid> - 2013-12-03 13:06 +0000
    Re: extracting a heapq in a for loop - there must be  more elegant solution Helmut Jarausch <jarausch@igpm.rwth-aachen.de> - 2013-12-04 09:39 +0000
  Re: extracting a heapq in a for loop - there must be  more elegant solution Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-12-03 15:56 +0200
    Re: extracting a heapq in a for loop - there must be  more elegant solution Helmut Jarausch <jarausch@igpm.rwth-aachen.de> - 2013-12-04 09:41 +0000
  Re: extracting a heapq in a for loop - there must be  more elegant solution Cameron Simpson <cs@zip.com.au> - 2013-12-04 08:13 +1100
    Re: extracting a heapq in a for loop - there must be  more elegant solution Helmut Jarausch <jarausch@igpm.rwth-aachen.de> - 2013-12-04 09:44 +0000
      Re: extracting a heapq in a for loop - there must be  more elegant solution Cameron Simpson <cs@zip.com.au> - 2013-12-05 13:29 +1100
  Re: extracting a heapq in a for loop - there must be more elegant solution Ian Kelly <ian.g.kelly@gmail.com> - 2013-12-03 14:43 -0700
  Re: extracting a heapq in a for loop - there must be more elegant solution Ned Batchelder <ned@nedbatchelder.com> - 2013-12-03 17:32 -0500

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