Unicode support in Python 2.7.8 - 16 bit

Chris Angelico rosuav at gmail.com
Tue Mar 7 17:21:14 EST 2017


On Wed, Mar 8, 2017 at 9:05 AM, John Nagle <nagle at animats.com> wrote:
>    How do I test if a Python 2.7.8 build was built for 32-bit
> Unicode?  (I'm dealing with shared hosting, and I'm stuck
> with their provided versions.)
>
> If I give this to Python 2.7.x:
>
>     sy = u'\U0001f60f'
>
> len(sy) is 1 on a Ubuntu 14.04LTS machine, but 2 on the
> Red Hat shared hosting machine.  I assume "1" indicates
> 32-bit Unicode capability, and "2" indicates 16-bit.
> It looks like  Python 2.x in 16-bit mode is using a UTF-16
> pair encoding, like Java. Is that right?  Is it documented
> somewhere?

That's correct. A narrow build will treat that as a pair of
surrogates. You may also be able to check this way:

>>> sys.maxunicode
1114111

> (Annoyingly, while the shared host has a Python 3, it's
> 3.2.3, which rejects "u" Unicode string constants and
> has other problems in the MySQL area.)

Yeah, you'll do well to get a newer Py3 than that. Fortunately, any
Linux old enough to be shipping 3.2 is likely to not depend on it in
any way, so you can install a new Py3 (maybe even 3.6) and shadow the
name "python3" with that. That's what I did when I was on Debian....
Squeeze, I think? and nothing newer than 3.2 was available.

Soon as you hit 3.3, the u"..." prefix becomes legal again, and
subsequent versions have added even more compatibility.

ChrisA


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