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Re: Idiosyncratic python

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Date Fri, 25 Sep 2015 02:57:54 +1000
Subject Re: Idiosyncratic python
From Chris Angelico <rosuav@gmail.com>
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On Fri, Sep 25, 2015 at 2:54 AM, Todd <toddrjen@gmail.com> wrote:
> Using list indexing with booleans in place of a ternary operator.
>
> a = False
> b = [var2, var1][a]
>
> Instead of:
>
> b = var1 if a else var2

Be careful - these are not semantically identical. The first one
evaluates both var1 and var2, while the second will evaluate only the
one it needs. This might be significant if they're not simple names.

ChrisA

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Idiosyncratic python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-09-24 16:02 +1000
  Re: Idiosyncratic python Paul Rubin <no.email@nospam.invalid> - 2015-09-23 23:16 -0700
    Re: Idiosyncratic python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-09-24 16:35 +1000
      Re: Idiosyncratic python Ben Finney <ben+python@benfinney.id.au> - 2015-09-24 16:54 +1000
        Re: Idiosyncratic python Steven D'Aprano <steve@pearwood.info> - 2015-09-25 11:08 +1000
      Re: Idiosyncratic python Terry Reedy <tjreedy@udel.edu> - 2015-09-24 02:54 -0400
  Re: Idiosyncratic python wxjmfauth@gmail.com - 2015-09-24 00:06 -0700
    Re: Idiosyncratic python Laurent Pointal <laurent.pointal@free.fr> - 2015-09-24 19:50 +0200
      Re: Idiosyncratic python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-24 21:05 +0100
  Re: Idiosyncratic python jmp <jeanmichel@sequans.com> - 2015-09-24 11:12 +0200
  Re: Idiosyncratic python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-24 14:09 +0100
  Re: Idiosyncratic python jmp <jeanmichel@sequans.com> - 2015-09-24 16:07 +0200
  Re: Idiosyncratic python Ian Kelly <ian.g.kelly@gmail.com> - 2015-09-24 08:26 -0600
  Re: Idiosyncratic python Chris Angelico <rosuav@gmail.com> - 2015-09-25 02:57 +1000
  Re: Idiosyncratic python jmp <jeanmichel@sequans.com> - 2015-09-24 20:04 +0200
  Re: Idiosyncratic python Ian Kelly <ian.g.kelly@gmail.com> - 2015-09-24 12:19 -0600
  Re: Idiosyncratic python Ned Batchelder <ned@nedbatchelder.com> - 2015-09-24 13:46 -0700
    Re: Idiosyncratic python Laura Creighton <lac@openend.se> - 2015-09-24 23:08 +0200
    Re: Idiosyncratic python Chris Angelico <rosuav@gmail.com> - 2015-09-25 07:49 +1000
    Re: Idiosyncratic python Steven D'Aprano <steve@pearwood.info> - 2015-09-25 10:55 +1000
  Re: Idiosyncratic python sohcahtoa82@gmail.com - 2015-09-24 15:32 -0700
  Re: Idiosyncratic python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-25 00:40 +0100
  Re: Idiosyncratic python Akira Li <4kir4.1i@gmail.com> - 2015-09-25 03:04 +0300
  Re: Idiosyncratic python Steven D'Aprano <steve@pearwood.info> - 2015-09-25 10:08 +1000

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