[Python-Dev] PEP 362 Third Revision

[Steven D'Aprano]

R. David Murray wrote:

>>> We know that a string cannot be both all-upper and all-lower at the same 
>>> time;
>> We know that because it's common wisdom for everyone (although who knows
>> what oddities the unicode consortium may come up with in the future).
> 
> Indeed, there is at least one letter that is used in both upper case and
> lower case, so the consortium could reasonably declare that it should
> return True for both isupper and islower :).

If you're talking about the German double-s ß, technically it is a lowercase 
letter and should be written as SS or SZ in uppercase.

Just to add complication, historically German used to have an uppercase ß, and 
in recent years some designers have started to reintroduce it.

(Note: I am not a German speaker, and everything I say above is taken from 
Wikipedia.)



-- 
Steven