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Re: Confused compare function :)

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Date Sat, 08 Dec 2012 17:50:46 +0000
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On 2012-12-08 07:17, Chris Angelico wrote:
> On Sat, Dec 8, 2012 at 6:01 PM, Terry Reedy <tjreedy@udel.edu> wrote:
>> Unfortunately, catching exceptions may be and often is as slow as the
>> redundant check and even multiple redundant checks.
>
> It depends on how often you're going to catch and how often just flow
> through. In Python, as in most other modern languages, exceptions only
> cost you when they get thrown. The extra check, though, costs you in
> the normal case.
>
That's where the .get method comes in handy:

MISSING = object()
...
value = my_dict.get(key, MISSING)
if value is not MISSING:
    ...

It could be faster if the dict often doesn't contain the key.

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Thread

Re: Confused compare function :) Bruno Dupuis <python.ml.bruno.dupuis@lisael.org> - 2012-12-06 01:19 +0100
  Re: Confused compare function :) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-06 00:42 +0000
    Re: Confused compare function :) Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-12-06 13:41 -0500
    Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-06 19:55 +0100
  Re: Confused compare function :) Rotwang <sg552@hotmail.co.uk> - 2012-12-06 03:22 +0000
    Re: Confused compare function :) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-06 04:32 +0000
      Re: Confused compare function :) Bruno Dupuis <python.ml.bruno.dupuis@lisael.org> - 2012-12-06 09:49 +0100
        Re: Confused compare function :) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-06 11:47 +0000
          Re: Confused compare function :) peter <pjmakey2@gmail.com> - 2012-12-06 08:55 -0300
            Re: Confused compare function :) Hans Mulder <hansmu@xs4all.nl> - 2012-12-06 14:32 +0100
              Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-07 00:47 +1100
          Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-06 23:14 +1100
            Re: Confused compare function :) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-07 22:16 +0000
              Re: Confused compare function :) Terry Reedy <tjreedy@udel.edu> - 2012-12-08 02:01 -0500
              Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-08 18:17 +1100
              Re: Confused compare function :) MRAB <python@mrabarnett.plus.com> - 2012-12-08 17:50 +0000
            Re: Confused compare function :) Ramchandra Apte <maniandram01@gmail.com> - 2012-12-08 19:07 -0800
              Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-09 14:22 +1100
                Re: Confused compare function :) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-09 07:39 +0000
            Re: Confused compare function :) Ramchandra Apte <maniandram01@gmail.com> - 2012-12-08 19:07 -0800
          Re: Confused compare function :) Neil Cerutti <neilc@norwich.edu> - 2012-12-06 13:51 +0000
            Re: Confused compare function :) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-07 02:55 +0000
              Re: Confused compare function :) Neil Cerutti <neilc@norwich.edu> - 2012-12-07 16:40 +0000
        Re: Confused compare function :) Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-12-06 14:33 +0100
          Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-07 00:58 +1100
            Re: Confused compare function :) Hans Mulder <hansmu@xs4all.nl> - 2012-12-06 15:21 +0100
              Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-07 01:28 +1100
          Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-06 15:22 +0100
          Re: Confused compare function :) Dave Angel <d@davea.name> - 2012-12-06 09:40 -0500
          Re: Confused compare function :) peter <pjmakey2@gmail.com> - 2012-12-06 11:46 -0300
          Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-06 17:16 +0100
          Re: Confused compare function :) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-12-06 16:52 +0000
          Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-06 18:08 +0100
          Re: Confused compare function :) MRAB <python@mrabarnett.plus.com> - 2012-12-06 17:10 +0000
          Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-06 18:31 +0100
          Re: Confused compare function :) MRAB <python@mrabarnett.plus.com> - 2012-12-06 17:52 +0000
          Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-06 19:25 +0100
          Re: Confused compare function :) Anatoli Hristov <tolidtm@gmail.com> - 2012-12-07 14:36 +0100
        Re: Confused compare function :) Rotwang <sg552@hotmail.co.uk> - 2012-12-06 19:24 +0000
      Re: Confused compare function :) Chris Angelico <rosuav@gmail.com> - 2012-12-06 20:34 +1100
      Re: Confused compare function :) Rotwang <sg552@hotmail.co.uk> - 2012-12-06 19:25 +0000

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