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Re: LBYL vs EAFP

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Date Tue, 5 Feb 2013 11:45:18 +1100
Subject Re: LBYL vs EAFP
From Chris Angelico <rosuav@gmail.com>
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Xref csiph.com comp.lang.python:38153

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On Tue, Feb 5, 2013 at 10:16 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
>     from numbers import Number
>     if isinstance(x, Number):
>         ...
>     else:
>         raise TypeError
>
>
> or Ask Forgiveness:
>
>     x + 0
>     ...
>
>
> where in both cases the ellipsis ... is the code I actually care about.

Caveat to my previous post: I would NOT indent the function body for
the sake of this check. I'd negate it:

if not isinstance(x, Number): raise TypeError

(hopefully with further information in the TypeError). I don't like
the code style that puts conditions, then more code, then error
handling - I prefer to fail-and-bail.

ChrisA

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Thread

LBYL vs EAFP Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-05 10:16 +1100
  Re: LBYL vs EAFP Chris Angelico <rosuav@gmail.com> - 2013-02-05 10:38 +1100
    Re: LBYL vs EAFP Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-05 03:52 +0000
      Re: LBYL vs EAFP Chris Angelico <rosuav@gmail.com> - 2013-02-05 16:19 +1100
  Re: LBYL vs EAFP Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-04 16:46 -0700
    Re: LBYL vs EAFP Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-05 04:52 +0000
      Re: LBYL vs EAFP Chris Angelico <rosuav@gmail.com> - 2013-02-05 16:20 +1100
        Re: LBYL vs EAFP Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-05 06:31 +0000
          Re: LBYL vs EAFP Pete Forman <petef4+usenet@gmail.com> - 2013-02-05 09:49 +0000
            Re: LBYL vs EAFP Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-02-05 23:04 +1100
              Re: LBYL vs EAFP Chris Angelico <rosuav@gmail.com> - 2013-02-05 23:25 +1100
      Re: LBYL vs EAFP Ian Kelly <ian.g.kelly@gmail.com> - 2013-02-04 22:40 -0700
  Re: LBYL vs EAFP Dave Angel <davea@davea.name> - 2013-02-04 18:55 -0500
  Re: LBYL vs EAFP Chris Angelico <rosuav@gmail.com> - 2013-02-05 11:45 +1100
  Re: LBYL vs EAFP Ethan Furman <ethan@stoneleaf.us> - 2013-02-04 16:26 -0800
  Re: LBYL vs EAFP Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-05 01:00 +0000
  Re: LBYL vs EAFP Terry Reedy <tjreedy@udel.edu> - 2013-02-05 02:53 -0500

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