RetroSearch Browse

Tue Sep 22 16:45:55 CEST 2015 · https://mail.python.org/pipermail/python-dev/2015-September/141762.html

On Tue, Sep 22, 2015 at 3:01 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:

> ... for times that
> don't exist, "dt.astimezone(utc).astimezone(dt.tzinfo)" will normalise
> them to be a time that actually exists in the original time zone, and
> that normalisation also effectively happens when calling
> "dt.timestamp()".
>

Yes.  In fact, if you consider the canonical bijection between timestamps
and datetimes (t = EPOCH + s * timedelta(0, 1); s = (t - EPOCH) /
timedelta(0, 1)), t.astimezone(utc) and t.timestamp() become the same up to
some annoying numerical details.  The same logic applies to
u.astimezone(tzinfo) and datetime.fromtimestamp(s).  Note that I
deliberately did not mark the units on the sketches: you can think of the
UTC axis to be labeled by datetimes or by numeric timestamps.

Note that dt != dt.astimezone(utc).astimezone(dt.tzinfo) is one way to
detect that dt is in a gap, but I recommend
(dt.replace(fold=0).utcoffset() > dt.replace(fold=1).utcoffset().)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20150922/d28e4e3d/attachment.html>

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://mail.python.org/pipermail/python-dev/2015-September/141762.html below:

[Python-Dev] PEP 495 accepted