.title() - annoying mistake

[Richard Damon]

On 3/22/21 4:20 PM, Christian Gollwitzer wrote:
> Am 22.03.21 um 16:03 schrieb Robert Latest:
>> Chris Angelico wrote:
>>> Cool thing is, nobody in Python needs to maintain anything here.
>>
>> That's great because I'm actually having trouble with sending log
>> messages over
>> the socket conection you helped me with, would you mind having a look?
>
> You misunderstood the "here".
>
> (native German as well, but I think it means "for keeping .title() up
> to date)
>
> I agree with Chris that .title() can be useful for "title-casing" a
> single character, whatever that means. It should be documented,
> though, that it is not suitable to title-case a string, not even in
> English.
>
>     Christian

Part of the difficulty in getting clear documentation for this is that
is it IS somewhat complicated. You title-case a string by Title-casing
the first character of each word (and the primary issue error that
started this was the definition of a 'word'), and lower casing the rest
of the word. The complication comes in that title-casing a character
99.99% of the time doesn't give you a character in title-case, but more
often in upper-case (or uncased). There are apparently only 31 actual
characters that are 'Title-Case'. Thus the action of 'title-casing' a
character is a bit strange to describe, especially to people used to
simple languages which don't have any of the characters that cause the
issue.

We don't seem to have a problme that upper doesn't always return a true
'upper-case', like for '1' because we realize that many character don't
have case, so it gets largly just assumed we know that. For title case,
the fact that almost all characters do NOT have a 'title-case' form
makes things a bit more awkward.

Yes, perhaps the documentation could be made a bit more clear. I do note
that the documentation for str.capitalize() does talk about using actual
title case characters if the first character is a digraph. Something
like that might make sense in the description of str.title()

Note, that str.istitle() doesn't actually check if the character is a
real 'title case' character, but that the string follows a rule similar
to what str.title() produces. I am not positive that its description
exactly matches what .title() produces, but it close, and the way it is
written, "Python's".istitle() is False, as the s at the end needs to be
uppper case to satisfy as ' is uncased, so the next cased character must
be upper case.

-- 
Richard Damon