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Re: Split a list into two parts based on a filter?

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Date Tue, 11 Jun 2013 09:12:58 +1000
Subject Re: Split a list into two parts based on a filter?
From Chris Angelico <rosuav@gmail.com>
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On Tue, Jun 11, 2013 at 9:10 AM, Tim Chase
<python.list@tim.thechases.com> wrote:
> 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.

Sure. If it's that good I might submit it to more-itertools... heh.

ChrisA

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Thread

Split a list into two parts based on a filter? roy@panix.com (Roy Smith) - 2013-06-10 16:34 -0400
  Re: Split a list into two parts based on a filter? Chris Angelico <rosuav@gmail.com> - 2013-06-11 08:50 +1000
  Re: Split a list into two parts based on a filter? Roel Schroeven <roel@roelschroeven.net> - 2013-06-11 00:50 +0200
    Re: Split a list into two parts based on a filter? Roy Smith <roy@panix.com> - 2013-06-11 00:11 -0400
      Re: Split a list into two parts based on a filter? Serhiy Storchaka <storchaka@gmail.com> - 2013-06-11 18:27 +0300
        Re: Split a list into two parts based on a filter? Roy Smith <roy@panix.com> - 2013-06-11 20:33 -0400
          Re: Split a list into two parts based on a filter? Phil Connell <pconnell@gmail.com> - 2013-06-12 07:32 +0100
            Re: Split a list into two parts based on a filter? Roy Smith <roy@panix.com> - 2013-06-12 07:39 -0400
              Re: Split a list into two parts based on a filter? Fábio Santos <fabiosantosart@gmail.com> - 2013-06-12 12:51 +0100
              Re: Split a list into two parts based on a filter? Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-12 15:06 +0300
              Re: Split a list into two parts based on a filter? Terry Reedy <tjreedy@udel.edu> - 2013-06-12 14:07 -0400
          Re: Split a list into two parts based on a filter? Serhiy Storchaka <storchaka@gmail.com> - 2013-06-12 19:28 +0300
          Re: Split a list into two parts based on a filter? Fábio Santos <fabiosantosart@gmail.com> - 2013-06-12 17:57 +0100
          Re: Split a list into two parts based on a filter? Terry Reedy <tjreedy@udel.edu> - 2013-06-12 14:47 -0400
          Re: Split a list into two parts based on a filter? Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-06-13 10:43 +0100
  Re: Split a list into two parts based on a filter? Chris Rebert <clp2@rebertia.com> - 2013-06-10 16:03 -0700
  Re: Split a list into two parts based on a filter? Tim Chase <python.list@tim.thechases.com> - 2013-06-10 18:10 -0500
  Re: Split a list into two parts based on a filter? Fábio Santos <fabiosantosart@gmail.com> - 2013-06-11 00:08 +0100
    Re: Split a list into two parts based on a filter? alex23 <wuwei23@gmail.com> - 2013-06-11 17:44 -0700
  Re: Split a list into two parts based on a filter? Chris Angelico <rosuav@gmail.com> - 2013-06-11 09:12 +1000
  Re: Split a list into two parts based on a filter? Peter Otten <__peter__@web.de> - 2013-06-11 02:11 +0200
  Re: Split a list into two parts based on a filter? Peter Otten <__peter__@web.de> - 2013-06-11 08:43 +0200
  Re: Split a list into two parts based on a filter? Jonas Geiregat <jonas@geiregat.org> - 2013-06-11 08:47 +0200
  Re: Split a list into two parts based on a filter? Fábio Santos <fabiosantosart@gmail.com> - 2013-06-11 14:48 +0100
    Re: Split a list into two parts based on a filter? rusi <rustompmody@gmail.com> - 2013-06-11 09:37 -0700
      Re: Split a list into two parts based on a filter? Fábio Santos <fabiosantosart@gmail.com> - 2013-06-11 18:05 +0100
        Re: Split a list into two parts based on a filter? rusi <rustompmody@gmail.com> - 2013-06-11 10:23 -0700
          Re: Split a list into two parts based on a filter? Chris Angelico <rosuav@gmail.com> - 2013-06-12 03:37 +1000
            Re: Split a list into two parts based on a filter? rusi <rustompmody@gmail.com> - 2013-06-11 11:13 -0700
          Re: Split a list into two parts based on a filter? Fábio Santos <fabiosantosart@gmail.com> - 2013-06-11 19:05 +0100
  Re: Split a list into two parts based on a filter? Joshua Landau <joshua.landau.ws@gmail.com> - 2013-06-11 15:22 +0100
  Re: Split a list into two parts based on a filter? Serhiy Storchaka <storchaka@gmail.com> - 2013-06-11 18:28 +0300
  Re: Split a list into two parts based on a filter? Chris Angelico <rosuav@gmail.com> - 2013-06-12 03:28 +1000
    Re: Split a list into two parts based on a filter? Roy Smith <roy@panix.com> - 2013-06-11 20:12 -0400
  Re: Split a list into two parts based on a filter? Peter Otten <__peter__@web.de> - 2013-06-11 20:13 +0200
  Re: Split a list into two parts based on a filter? Peter Otten <__peter__@web.de> - 2013-06-11 20:18 +0200
  Re: Split a list into two parts based on a filter? Chris Angelico <rosuav@gmail.com> - 2013-06-12 04:27 +1000
  Re: Split a list into two parts based on a filter? Roel Schroeven <roel@roelschroeven.net> - 2013-06-11 22:22 +0200

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