Handling 3 operands in an expression without raising an exception

[Νίκος]

Στις 26/9/2013 1:41 μμ, ο/η Antoon Pardon έγραψε:
> Op 26-09-13 12:18, Νίκος schreef:
>> Στις 26/9/2013 1:12 μμ, ο/η Antoon Pardon έγραψε:
>>> Op 26-09-13 11:56, Νίκος schreef:
>>>> Στις 26/9/2013 11:55 πμ, ο/η Nobody έγραψε:
>>>>> On Thu, 26 Sep 2013 10:26:48 +0300, Νίκος wrote:
>>>>>
>>>>>> How can i wrote the two following lines so for NOT to throw out
>>>>>> KeyErrors when a key is missing?
>>>>>>
>>>>>> city = gi.time_zone_by_addr( os.environ['HTTP_CF_CONNECTING_IP'] ) or
>>>>>> gi.time_zone_by_addr( os.environ['REMOTE_ADDR'] ) or
>>>>>> "Άγνωστη Πόλη"
>>>>>
>>>>> tz = None
>>>>> ip = os.environ.get('HTTP_CF_CONNECTING_IP')
>>>>> if ip:
>>>>>      tz = gi.time_zone_by_addr(ip)
>>>>> if not tz:
>>>>>      ip = os.environ.get('REMOTE_ADDR')
>>>>>      if ip:
>>>>>        tz = gi.time_zone_by_addr(ip)
>>>>> if not tz:
>>>>>      tz = "ÎγνÏÏÏη Î Ïλη"
>>>>>
>>>>> Likewise for the hostname.
>>>>>
>>>>
>>>> Its logic is simple and straightforward but too many lines:
>>>>
>>>> host = socket.gethostbyaddr( os.environ.get('HTTP_CF_CONNECTING_IP') or
>>>> os.environ.get('REMOTE_ADDR') or  "Άγνωστη Προέλευση" )
>>>>
>>>> this is much better in my opinion and straighforward also and more clear
>>>> to read:
>>>
>>> No it is not and you prove that in the very next line.
>>>
>>>> it doens't work though:
>>>
>>> If it doesn't do what you think it should do then it is not straight
>>> forward or clear, at least not to you.
>>
>> It is far better than the ifs, even easier to read, i was just missing a
>> [0] at the end.
>>
>> host = socket.gethostbyaddr( os.environ.get('HTTP_CF_CONNECTING_IP') or
>> os.environ.get('REMOTE_ADDR') or  "Άγνωστη Προέλευση" )[0]
>
> No it is not. Your purpose was to have a line that wouldn't throw an
> exception even if some environ variables were not available. That
> means it shouldn't throw an exception when I execute the code. Guess
> what happens:
>
>>>> 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.