Not x.islower() has different output than x.isupper() in list output...

[Chris Angelico]

On Tue, May 3, 2016 at 11:01 PM, DFS <nospam at dfs.com> wrote:
> On 5/3/2016 8:00 AM, Chris Angelico wrote:
>>
>> On Tue, May 3, 2016 at 9:25 PM, Jussi Piitulainen
>> <jussi.piitulainen at helsinki.fi> wrote:
>>>
>>> Chris Angelico writes:
>>>
>>>> This assumes, of course, that there is a function swapcase which can
>>>> return a string with case inverted. I'm not sure such a function
>>>> exists.
>>>
>>>
>>>    str.swapcase("foO")
>>>    'FOo'
>>
>>
>> I suppose for this discussion it doesn't matter if it's imperfect.
>
>
>
> What was imperfect?

It doesn't invert, the way numeric negation does. And if you try to
define exactly what it does, you'll come right back to
isupper()/islower(), so it's not much help in defining those.

ChrisA