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[Python-Dev] Unicode minus sign in numeric conversions

Guido van Rossum guido at python.org
Sun Jun 9 00:30:52 CEST 2013 
[Diverting to python-ideas, since this isn't as clear-cut as you think.]

Why exactly is that expected behavior? What's the use case? (Surely
you don't have a keyboard that generates \u2212 when you hit the minus
key? :-)

Is there a Unicode standard for parsing numbers? IIRC there are a
variety of other things marked as "digits" in the Unicode standard --
do we do anything with those? If we do anything we should be
consistent. For now, I think we *are* consistent -- we only support
the ASCII representation of numbers. (And that's the only
representation we generate as output as well -- think about symmetry
too.)

This page scares me: http://en.wikipedia.org/wiki/Numerals_in_Unicode

--Guido

On Sat, Jun 8, 2013 at 2:49 PM, Łukasz Langa <lukasz at langa.pl> wrote:
> Expected behaviour:
>>>> float('\N{MINUS SIGN}12.34')
> -12.34
>
>
> Current behaviour:
> Traceback (most recent call last):
> ...
> ValueError: could not convert string to float: '−12.34'
>
>
> Please note: '\N{MINUS SIGN}' == '\u2212'
>
> --
> Best regards,
> Łukasz Langa
>
> WWW: http://lukasz.langa.pl/
> Twitter: @llanga
> IRC: ambv on #python-dev
>
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-- 
--Guido van Rossum (python.org/~guido)
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