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Re: lambda in list comprehension acting funny

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Sender "John O'Hagan" <johnmohagan@gmail.com>
Date Thu, 12 Jul 2012 15:29:42 +1000
From John O'Hagan <research@johnohagan.com>
To python-list@python.org
Subject Re: lambda in list comprehension acting funny
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On Wed, 11 Jul 2012 13:21:34 -0700 (PDT)
John Ladasky <john_ladasky@sbcglobal.net> wrote:

> Exactly.  It's threads like these which remind me why I never use lambda.  I
> would rather give a function an explicit name and adhere to the familiar
> Python syntax, despite the two extra lines of code.  I don't even like the
> name "lambda".  It doesn't tell you what it is (unless you're John McCarthy),
> a function that you won't re-use and so you don't really need to give it a
> persistent name.  
> 
> I haven't seen any lambdas in any Python library code, or in any of the
> third-party modules I use (numpy, matplotlib, Biopython).  Do they exist?
> Because I have not been forced to do so, I haven't retained a space in the
> top drawer of my programming brain for lambda.
[...]

+1 about the name, -1 about the usefulness. For example it's a clear and
concise way to pass a key argument to min, max, sort and friends:

sort(seq, key=lambda x: x.a)

The alternative is to have trivial function definitions floating around the
namespace which readers of the code have to search for.

--
John

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Thread

lambda in list comprehension acting funny Daniel Fetchinson <fetchinson@googlemail.com> - 2012-07-11 08:41 +0200
  Re: lambda in list comprehension acting funny "Colin J. Williams" <cjw@ncf.ca> - 2012-07-11 06:28 -0400
    Re: lambda in list comprehension acting funny Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-11 10:34 -0600
      Re: lambda in list comprehension acting funny 88888 Dihedral <dihedral88888@googlemail.com> - 2012-07-11 20:39 -0700
        Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-12 03:51 +0000
          Re: lambda in list comprehension acting funny 88888 Dihedral <dihedral88888@googlemail.com> - 2012-07-11 22:04 -0700
            Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-12 06:18 +0000
              Re: lambda in list comprehension acting funny Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-07-12 08:40 +0100
      Re: lambda in list comprehension acting funny 88888 Dihedral <dihedral88888@googlemail.com> - 2012-07-11 20:39 -0700
  Re: lambda in list comprehension acting funny woooee <woooee@gmail.com> - 2012-07-11 11:38 -0700
    Re: lambda in list comprehension acting funny John Ladasky <john_ladasky@sbcglobal.net> - 2012-07-11 13:21 -0700
      Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-12 00:52 +0000
      Re: lambda in list comprehension acting funny Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-07-11 21:05 -0400
        Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-12 03:53 +0000
          Re: lambda in list comprehension acting funny Terry Reedy <tjreedy@udel.edu> - 2012-07-12 00:24 -0400
          Re: lambda in list comprehension acting funny Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-07-12 00:39 -0400
            Re: lambda in list comprehension acting funny Robert Miles <robertmiles@teranews.com> - 2012-08-15 19:26 -0500
      Re: lambda in list comprehension acting funny John O'Hagan <research@johnohagan.com> - 2012-07-12 15:29 +1000
      Re: lambda in list comprehension acting funny Robert Kern <robert.kern@gmail.com> - 2012-07-12 10:06 +0100
    Re: lambda in list comprehension acting funny Hans Mulder <hansmu@xs4all.nl> - 2012-07-12 00:22 +0200
    Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-11 23:47 +0000
      Re: lambda in list comprehension acting funny Daniel Fetchinson <fetchinson@googlemail.com> - 2012-07-12 04:54 +0200
  Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-12 03:59 +0000
    Re: lambda in list comprehension acting funny Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-12 10:53 -0600
    Re: lambda in list comprehension acting funny Rotwang <sg552@hotmail.co.uk> - 2012-07-12 18:23 +0100
      Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-13 02:20 +0000
  Re: lambda in list comprehension acting funny rusi <rustompmody@gmail.com> - 2012-07-12 21:33 -0700
    Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-13 06:36 +0000
      Re: lambda in list comprehension acting funny rusi <rustompmody@gmail.com> - 2012-07-13 06:44 -0700
        Re: lambda in list comprehension acting funny rusi <rustompmody@gmail.com> - 2012-07-13 07:45 -0700
        RE: lambda in list comprehension acting funny "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-07-13 16:12 +0000
          Re: lambda in list comprehension acting funny rusi <rustompmody@gmail.com> - 2012-07-13 09:46 -0700
            Re: lambda in list comprehension acting funny Chris Angelico <rosuav@gmail.com> - 2012-07-14 03:20 +1000
          Re: lambda in list comprehension acting funny Hans Mulder <hansmu@xs4all.nl> - 2012-07-13 19:53 +0200
            RE: lambda in list comprehension acting funny "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-07-13 18:06 +0000
            Re: lambda in list comprehension acting funny Ian Kelly <ian.g.kelly@gmail.com> - 2012-07-13 12:54 -0600
              Re: lambda in list comprehension acting funny Hans Mulder <hansmu@xs4all.nl> - 2012-07-13 21:26 +0200
              Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-14 23:29 +0000
                Re: lambda in list comprehension acting funny Chris Angelico <rosuav@gmail.com> - 2012-07-15 10:49 +1000
                Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-15 08:32 +0000
                Re: lambda in list comprehension acting funny Chris Angelico <rosuav@gmail.com> - 2012-07-15 18:44 +1000
                Re: lambda in list comprehension acting funny Hans Mulder <hansmu@xs4all.nl> - 2012-07-15 21:25 +0200
                Re: lambda in list comprehension acting funny Terry Reedy <tjreedy@udel.edu> - 2012-07-15 06:27 -0400
            Re: lambda in list comprehension acting funny rusi <rustompmody@gmail.com> - 2012-07-13 19:31 -0700
              Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-14 03:43 +0000
                Re: lambda in list comprehension acting funny rusi <rustompmody@gmail.com> - 2012-07-13 21:53 -0700
                Re: lambda in list comprehension acting funny Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-14 07:46 +0000
        Re: lambda in list comprehension acting funny Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-07-13 13:47 -0400

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