[Python-3000] __format__ and datetime

[Guido van Rossum]

On 9/11/07, skip at pobox.com <skip at pobox.com> wrote:
>
>     Skip> I would like to see an analog to %S which preserves fractions of a
>     Skip> second as the default formatting for time and datetime objects
>     Skip> does:
>
>     Skip> >>> print(now)
>     Skip> 2007-09-10 22:07:53.654774
>
>     Guido> Right. It's odd that there's nothing explicit that exactly
>     Guido> produces the default. (Though floats have this issue too -- I
>     Guido> wish it could be fixed there too.)
>
> Looking at the libref doc for time.strftime and the strftime(3) man pages on
> Solaris 10, Mac OS X and CentOS 4, I see that %f is unused ("f" is mnemonic
> for "fractions" of a second).  Maybe after a little more investigation and
> not endless amounts of discussion this could be added to Python as the way
> to represent the fractions of seconds as an int representing microseconds.
> For example, the above example could be specified by
>
>     %Y-%m-%d %H:%M:%S.%f
>
> Thinking about future advances in timekeeping, is microseconds too short?
> Maybe "%N" for "nanoseconds"?

No, the datetime module is explicitly defined to use microseconds. I
don't expect there to be a practical use for nanoseconds (even
microseconds are doubtful, but useful since one might want unique
timestamps for more than 1000 events per second).

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)