Handling 3 operands in an expression without raising an exception

[Νίκος]

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:

it doens't work though:

ima thinkin that the [0] is missign at the end so i cna grab the first 
item of the returnign tuple:

host = socket.gethostbyaddr( os.environ.get('HTTP_CF_CONNECTING_IP') or 
os.environ.get('REMOTE_ADDR') or  "Άγνωστη Προέλευση" )[0]

for the first two element if they are beign return i cna understand the 
[0] at the end but what about if the string is being return wouldnt that 
return just the 'A' of the string?

Is it correct to write it liek this?