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

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Date Wed, 12 Jun 2013 03:28:34 +1000
Subject Re: Split a list into two parts based on a filter?
From Chris Angelico <rosuav@gmail.com>
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On Wed, Jun 12, 2013 at 1:28 AM, Serhiy Storchaka <storchaka@gmail.com> wrote:
> 11.06.13 01:50, Chris Angelico написав(ла):
>
>> On Tue, Jun 11, 2013 at 6:34 AM, Roy Smith <roy@panix.com> wrote:
>>>
>>> new_songs = [s for s in songs if s.is_new()]
>>> old_songs = [s for s in songs if not s.is_new()]
>>
>>
>> Hmm. Would this serve?
>>
>> old_songs = songs[:]
>> new_songs = [songs.remove(s) or s for s in songs if s.is_new()]
>
>
> O(len(songs)**2) complexity.

Which isn't significant if len(songs) is low. We weren't told the
relative costs - is the is_new call ridiculously expensive? Everything
affects algorithmic choice.

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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