[Python-Dev] iso8601 parsing

[Chris Barker]

+1 on a classmethod constructor
+0 on a based-on-type default constructor

+inf on SOMETHING!

Let's get passed the bike shedding and make this work!

-CHB


On Wed, Oct 25, 2017 at 2:18 PM, Alex Walters <tritium-list at sdamon.com>
wrote:

>
>
> > -----Original Message-----
> > From: Alexander Belopolsky [mailto:alexander.belopolsky at gmail.com]
> > Sent: Wednesday, October 25, 2017 4:33 PM
> > To: Alex Walters <tritium-list at sdamon.com>
> > Cc: Elvis Pranskevichus <elprans at gmail.com>; Python-Dev <python-
> > dev at python.org>; Chris Barker <chris.barker at noaa.gov>
> > Subject: Re: [Python-Dev] iso8601 parsing
> >
> > On Wed, Oct 25, 2017 at 3:48 PM, Alex Walters <tritium-list at sdamon.com>
> > wrote:
> > >  Why make parsing ISO time special?
> >
> > It's not the ISO format per se that is special, but parsing of str(x).
> > For all numeric types, int, float, complex and even
> > fractions.Fraction, we have a roundtrip invariant T(str(x)) == x.
> > Datetime types are a special kind of numbers, but they don't follow
> > this established pattern.  This is annoying when you deal with time
> > series where it is common to have text files with a mix of dates,
> > timestamps and numbers.  You can write generic code to deal with ints
> > and floats, but have to special-case anything time related.
>
> >>> repr(datetime.datetime.now())
> 'datetime.datetime(2017, 10, 25, 17, 16, 20, 973107)'
>
> You can already roundtrip the repr of datetime objects with eval (if you
> care to do so).  You get iso formatting from a method on dt objects, I
> don’t see why it should be parsed by anything but a classmethod.
>
>
>


-- 

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
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Chris.Barker at noaa.gov
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