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Date: Mon, 10 Jun 2013 18:10:22 -0500
From: Tim Chase <python.list@tim.thechases.com>
To: Chris Angelico <rosuav@gmail.com>
Subject: Re: Split a list into two parts based on a filter?
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Xref: csiph.com comp.lang.python:47615

On 2013-06-11 08:50, Chris Angelico wrote:
> The iterator version strikes my fancy. Maybe this isn't of use to
> you, but I'm going to try my hand at making one anyway.
> 
> >>> def iterpartition(pred,it):
> 	"""Partition an iterable based on a predicate.
> 
> 	Returns two iterables, for those with pred False and those
> True.""" falses,trues=[],[]

This is really nice.  I think the only major modification I'd make is
to use a collections.deque() instead of lists here:

  trues, falses = collections.deque(), collections.deque()

as I seem to recall that list.pop(0) has some performance issues if
it gets long, while the deque is optimized for fast (O(1)?) push/pop
on either end.

-tkc