In Turkish there is a character when you capitalize "i" and it's written as "İ". When I use str.lower method, it seems like it works just fine because it prints the character I expected(i). But the problem is when I compare it to normal "i" character (without lowering), the character which is "İ" then became "i" has 2 digits(or length) so same words are no more the same. (ex. the word "issue" and the word "İssue"-->"issue" are not the same when compared) This is a big issue in terms of word counter softwares.

This is not a bug, but an issue with the way the Unicode standard defines the lowercase of dotted I.

See #34723

Fortunately, Unicode will (hopefully!) fix this in revision 14.0, which is scheduled to be included in Python 3.10.

Until then, perhaps the simplest way to solve this is that if you are processing Turkish text, change your call to .lower() to .replace('İ', 'I').lower()

Thanks for the answer. I will keep that in mind when posting another
"issue" instead of naming them as "bug".

Steven D'Aprano <report@bugs.python.org>, 25 Oca 2021 Pzt, 13:22 tarihinde
şunu yazdı:

>
> Steven D'Aprano <steve+python@pearwood.info> added the comment:
>
> This is not a bug, but an issue with the way the Unicode standard defines
> the lowercase of dotted I.
>
> See #34723
>
> Fortunately, Unicode will (hopefully!) fix this in revision 14.0, which is
> scheduled to be included in Python 3.10.
>
> Until then, perhaps the simplest way to solve this is that if you are
> processing Turkish text, change your call to .lower() to .replace('İ',
> 'I').lower()
>
> ----------
> nosy: +steven.daprano
> resolution:  -> not a bug
> stage:  -> resolved
> status: open -> closed
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue43020>
> _______________________________________
>