Re: Handling 3 operands in an expression without raising an exception

From	Νίκος <nikos.gr33k@gmail.com>
Newsgroups	comp.lang.python
Subject	Re: Handling 3 operands in an expression without raising an exception
Date	2013-09-26 15:39 +0300
Organization	A noiseless patient Spider
Message-ID	<l219tq$o2c$1@dont-email.me> (permalink)
References	(3 earlier) <mailman.345.1380190345.18130.python-list@python.org> <l211m1$f3b$1@dont-email.me> <mailman.348.1380192089.18130.python-list@python.org> <l213jr$p9j$1@dont-email.me> <mailman.350.1380194717.18130.python-list@python.org>

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Στις 26/9/2013 2:24 μμ, ο/η Dave Angel έγραψε:
> On 26/9/2013 06:51, Νίκος wrote:
>
>     <SNIP>
>>>>>> socket.gethostbyaddr( os.environ.get('HTTP_CF_CONNECTING_IP') or
>>> os.environ.get('REMOTE_ADDR') or  "Άγνωστη Προέλευση" )[0]
>>> Traceback (most recent call last):
>>>     File "<stdin>", line 1, in <module>
>>> socket.gaierror: [Errno -2] Name or service not known
>>>
>>> You are just illustrating your lack of basic understaning.
>>
>> I'm surepirsed, becaus eon my domain [superhost.gr] the same lien of
>> code works withnout an error and it display the 'host' fileds properly.
>>
>> Perhaps its failing via shell or you do not have a web server installed
>> to prepare the enviromental variables or i dont know what else to hink.
>>
>> But in my website this code runs at the probelm with no problem.
>>
> In Python 3.3, but not on a web server, I get:
>
>
>>>> import socket
>>>> socket.gethostbyaddr("unknown")[0]
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
> socket.gaierror: [Errno -2] Name or service not known
>>>>
>
> Question, do you get the same result on your server?  (You can put the
> Greek string in place of "unknown" of course)
>
> If so, then the default value makes no sense;  it'll cause an exception
> if it's ever used.  If you insist on sticking to expressions (no
> try/catch, no if statements), then perhaps you should default to a
> string representing a domain which will always exist.

Yes, you are right, in my shell it fails too givign the same error 
message as yours, while on the other had in the websste is working.

Can you explain this please?
why doesnt it fail to both enviroments?

Thread

Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 10:26 +0300
  Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-26 10:48 +0300
    Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 10:51 +0300
      Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-26 11:12 +0300
        Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 11:39 +0300
          Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 11:46 +0300
            Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 11:50 +0300
              Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-26 12:20 +0300
          Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-26 12:04 +0300
            Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 12:45 +0300
          Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 11:07 +0200
            Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 12:31 +0300
              Re: Handling 3 operands in an expression without raising an exception Maarten <maarten.sneep@knmi.nl> - 2013-09-26 02:52 -0700
              Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 12:01 +0200
              Re: Handling 3 operands in an expression without raising an exception "James Harris" <james.harris.1@gmail.com> - 2013-09-26 11:53 +0100
          Re: Handling 3 operands in an expression without raising an exception alex23 <wuwei23@gmail.com> - 2013-09-27 10:05 +1000
        Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-26 18:41 +1000
        Re: Handling 3 operands in an expression without raising an exception Tim Golden <mail@timgolden.me.uk> - 2013-09-26 09:47 +0100
  Re: Handling 3 operands in an expression without raising an exception Nobody <nobody@nowhere.com> - 2013-09-26 09:55 +0100
    Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 12:56 +0300
      Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 12:12 +0200
        Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 13:18 +0300
          Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 12:41 +0200
            Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 13:51 +0300
              Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 13:07 +0200
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 14:25 +0300
                Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 13:47 +0200
                Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-26 14:42 +0000
              Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-26 11:24 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 15:39 +0300
                Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-26 14:53 +0200
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 16:34 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-26 14:22 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-26 19:58 +0300
                Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-26 20:16 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-27 01:14 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-26 22:55 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-27 12:19 +0300
                Re: Handling 3 operands in an expression without raising an exception Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-27 09:26 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-27 13:04 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-27 10:43 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-27 14:15 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-27 12:17 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-27 15:51 +0300
                Re: Handling 3 operands in an expression without raising an exception rusi <rustompmody@gmail.com> - 2013-09-28 10:29 -0700
                Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-27 15:16 +0000
                Re: Handling 3 operands in an expression without raising an exception Grant Edwards <invalid@invalid.invalid> - 2013-09-27 16:04 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-27 19:47 +0300
                Re: Handling 3 operands in an expression without raising an exception Neil Cerutti <neilc@norwich.edu> - 2013-09-27 16:56 +0000
                Re: Handling 3 operands in an expression without raising an exception Grant Edwards <invalid@invalid.invalid> - 2013-09-27 17:00 +0000
                Re: Handling 3 operands in an expression without raising an exception Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-27 13:19 -0400
                Re: Handling 3 operands in an expression without raising an exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-09-27 18:32 +0100
                Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-27 18:49 +0000
                Re: Handling 3 operands in an expression without raising an exception Grant Edwards <invalid@invalid.invalid> - 2013-09-27 18:54 +0000
                Re: Handling 3 operands in an expression without raising an exception Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-27 15:21 -0400
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-28 01:06 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-27 22:26 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-28 12:33 +0300
                Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-28 20:19 +1000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-28 16:23 +0300
                Re: Handling 3 operands in an expression without raising an exception Andreas Perstinger <andipersti@gmail.com> - 2013-09-28 17:02 +0200
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-28 19:14 +0300
                Re: Handling 3 operands in an expression without raising an exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-09-28 18:53 +0100
                Re: Handling 3 operands in an expression without raising an exception Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-28 14:21 -0400
                Re: Handling 3 operands in an expression without raising an exception Zero Piraeus <z@etiol.net> - 2013-09-28 15:38 -0300
                Re: Handling 3 operands in an expression without raising an exception Neil Cerutti <neilc@norwich.edu> - 2013-09-30 11:32 +0000
                Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-30 21:53 +1000
                Re: Handling 3 operands in an expression without raising an exception Neil Cerutti <neilc@norwich.edu> - 2013-09-30 12:56 +0000
                Re: Handling 3 operands in an expression without raising an exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-09-28 19:45 +0100
                Re: Handling 3 operands in an expression without raising an exception Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-28 19:20 +0000
                Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-29 09:04 +1000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-29 10:35 +0300
                Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-29 12:35 +0300
                Re: Handling 3 operands in an expression without raising an exception Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-09-29 09:48 +0000
                Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-29 14:04 +0300
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-29 14:14 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-29 11:27 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-29 14:34 +0300
                Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-29 21:15 +0000
                Re: Handling 3 operands in an expression without raising an exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-09-30 16:07 +0100
                Re: Handling 3 operands in an expression without raising an exception Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-09-29 15:24 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-29 09:50 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-29 13:17 +0300
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-29 10:57 +0000
                Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-29 23:58 +1000
                Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-29 21:01 +0000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-29 14:06 +0300
                Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-29 12:48 +0200
                Re: Handling 3 operands in an expression without raising an exception Piet van Oostrum <piet@vanoostrum.org> - 2013-09-29 13:24 -0400
                Re: Handling 3 operands in an expression without raising an exception MRAB <python@mrabarnett.plus.com> - 2013-09-29 18:44 +0100
                Re: Handling 3 operands in an expression without raising an exception Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-29 14:45 -0400
                Re: Handling 3 operands in an expression without raising an exception Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-09-30 16:05 +0100
                Re: Handling 3 operands in an expression without raising an exception Ben Finney <ben+python@benfinney.id.au> - 2013-09-29 11:35 +1000
                Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-28 11:59 +1000
                Re: Handling 3 operands in an expression without raising an exception Νίκος <nikos.gr33k@gmail.com> - 2013-09-28 12:14 +0300
                Re: Handling 3 operands in an expression without raising an exception Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-09-28 15:53 +0200
                Re: Handling 3 operands in an expression without raising an exception Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-28 12:15 -0400
                Re: Handling 3 operands in an expression without raising an exception Robert Kern <robert.kern@gmail.com> - 2013-09-28 12:18 +0100
                Re: Handling 3 operands in an expression without raising an exception giacomo boffi <pecore@pascolo.net> - 2013-09-29 17:28 +0200
                Re: Handling 3 operands in an expression without raising an exception Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-29 12:07 -0400
                Re: Handling 3 operands in an expression without raising an exception giacomo boffi <pecore@pascolo.net> - 2013-09-29 23:39 +0200
                Re: Handling 3 operands in an expression without raising an exception giacomo boffi <pecore@pascolo.net> - 2013-09-29 23:49 +0200
                Re: Handling 3 operands in an expression without raising an exception Chris Angelico <rosuav@gmail.com> - 2013-09-30 02:18 +1000
                Re: Handling 3 operands in an expression without raising an exception Dave Angel <davea@davea.name> - 2013-09-26 20:37 +0000
      Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-26 14:38 +0000
      Re: Handling 3 operands in an expression without raising an exception Denis McMahon <denismfmcmahon@gmail.com> - 2013-09-26 14:38 +0000
  Re: Handling 3 operands in an expression without raising an exception Gene Heskett <gheskett@wdtv.com> - 2013-09-29 13:32 -0400

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