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Re: LangWart: Method congestion from mutate multiplicty

Newsgroups comp.lang.python
Date 2013-02-11 04:53 -0800
References (1 earlier) <5115c455$0$6574$c3e8da3$5496439d@news.astraweb.com> <d405822d-2252-4a85-8ab2-38ca88963d91@googlegroups.com> <511784b3$0$29988$c3e8da3$5496439d@news.astraweb.com> <6b7d7299-7ce3-401f-a950-04cea18af399@googlegroups.com> <51183d05$0$29992$c3e8da3$5496439d@news.astraweb.com>
Message-ID <d963cd0b-a387-413e-8e21-b09e07d1640d@googlegroups.com> (permalink)
Subject Re: LangWart: Method congestion from mutate multiplicty
From Rick Johnson <rantingrickjohnson@gmail.com>

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On Sunday, February 10, 2013 6:36:20 PM UTC-6, Steven D'Aprano wrote:
> Rick Johnson wrote:
> > On Sunday, February 10, 2013 5:29:54 AM UTC-6, Steven D'Aprano wrote:
> >> Rick wrote:
> > [...]
> > Steven, the definition of flatten (as relates to sequences) is very, VERY
> > simple:
> > 
> >     Return a new sequence that is the result of reducing
> >     a nested sequence of sequences into a single depth
> >     sequence.
> 
> Very, VERY simple until you actually implement this function, and discover
> that it does too much e.g.

I would implement it as a method of sequence types, but i digress!

> flatten([None, 23, [1, 2, 3], Point(x=2, y=3), ["spam", "ham"]])
> => [None, 23, 1, 2, 3, 2, 3, 's', 'p', 'a', 'm', 'h', 'a', 'm']
> 
> So people who have *actually programmed*, instead of just talking about
> programming, have discovered that in practice you need to treat some
> sequences as primitives that don't get expanded.

Which primitive(s) should NOT have been expanded in your opinion? The "Point" object? I agree, that's why MY implementation would call seq.flatten() on all sub-sequences THEREBY allowing each subtype to define it's own flatten behavior. Of course the default behavior of the SequenceBase#flatten would be to flatten everything. 

However, ImmutableSequence Types would not flatten. In your example ["spam", "ham"] would not be expanded to ['s', 'p', 'a', 'm', 'h', 'a', 'm']. psst: strings and tuples are immutable!


I'm not convinced that flattening immutable types is a good idea anyway, because heck, they're designed to be immutable! I suppose if we are not flattening "in-place" it really would not matter though. Creating a new immutable object that is the result of reordering an existing immutable object's values is not mutation.

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LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-08 17:50 -0800
  Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-09 14:36 +1100
    Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-09 19:54 -0800
      Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-10 15:20 +1100
      Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-09 20:53 -0800
        Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 01:29 +1100
          Re: LangWart: Method congestion from mutate multiplicty Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-10 14:03 -0500
            Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:11 +1100
          Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 13:28 -0800
            Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:10 +1100
              Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 17:14 -0800
          Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-11 08:51 +1100
          Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 14:01 -0800
      Re: LangWart: Method congestion from mutate multiplicty Terry Reedy <tjreedy@udel.edu> - 2013-02-10 03:39 -0500
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 10:45 -0800
          Re: LangWart: Method congestion from mutate multiplicty Terry Reedy <tjreedy@udel.edu> - 2013-02-10 16:44 -0500
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:11 +1100
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 10:45 -0800
      Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-10 22:29 +1100
        Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-11 00:24 +1100
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 01:00 +1100
        Re: LangWart: Method congestion from mutate multiplicty Tim Chase <python.list@tim.thechases.com> - 2013-02-10 07:52 -0600
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 15:59 -0800
          Re: LangWart: Method congestion from mutate multiplicty Tim Chase <python.list@tim.thechases.com> - 2013-02-10 18:12 -0600
            Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 17:24 -0800
            Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 17:24 -0800
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:36 +1100
            Re: LangWart: Method congestion from mutate multiplicty MRAB <python@mrabarnett.plus.com> - 2013-02-11 02:03 +0000
            Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 04:53 -0800
              Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-12 00:27 +1100
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:55 -0800
                Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-11 21:28 -0800
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-12 12:46 -0800
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-12 12:46 -0800
                Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-11 20:55 -0800
          Re: LangWart: Method congestion from mutate multiplicty alex23 <wuwei23@gmail.com> - 2013-02-10 18:05 -0800
            Re: LangWart: Method congestion from mutate multiplicty Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-11 07:19 +0000
            Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-11 18:24 +1100
            Re: LangWart: Method congestion from mutate multiplicty Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-02-11 07:35 +0000
            Re: LangWart: Method congestion from mutate multiplicty Tim Chase <tim@thechases.com> - 2013-02-11 06:04 -0600
            Re: LangWart: Method congestion from mutate multiplicty Serhiy Storchaka <storchaka@gmail.com> - 2013-02-11 19:07 +0200
      Re: LangWart: Method congestion from mutate multiplicty Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-10 13:30 +0000
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 16:25 -0800
          Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-11 11:42 +1100
        Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 16:25 -0800
      Re: LangWart: Method congestion from mutate multiplicty Mark Janssen <dreamingforward@gmail.com> - 2013-02-10 10:45 -0800
    Re: LangWart: Method congestion from mutate multiplicty 88888 Dihedral <dihedral88888@googlemail.com> - 2013-02-10 06:33 -0800
  Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-09 15:51 +1100
    Re: LangWart: Method congestion from mutate multiplicty alex23 <wuwei23@gmail.com> - 2013-02-10 17:56 -0800
      Re: LangWart: Method congestion from mutate multiplicty Chris Angelico <rosuav@gmail.com> - 2013-02-12 19:06 +1100
  Re: LangWart: Method congestion from mutate multiplicty Neil Hodgson <nhodgson@iinet.net.au> - 2013-02-10 20:53 +1100
    Re: LangWart: Method congestion from mutate multiplicty Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-10 22:30 +1100
    Re: LangWart: Method congestion from mutate multiplicty Rick Johnson <rantingrickjohnson@gmail.com> - 2013-02-10 10:55 -0800
      Re: LangWart: Method congestion from mutate multiplicty Neil Hodgson <nhodgson@iinet.net.au> - 2013-02-11 08:57 +1100

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