[Numpy-discussion] About ready to start 1.8 release process.

Chris Barker - NOAA Federal chris.barker@noaa....
Mon Aug 12 18:16:21 CDT 2013


On Mon, Aug 12, 2013 at 3:14 PM, Charles R Harris
<charlesr.harris@gmail.com> wrote:

>> > Datetime64 will not be modified in this release.
>>
>> I now there is neither the time nor the will for all that it needs,
>> but please, please, please, can we yank out the broken timezone
>> handling at least?
>>
>> https://github.com/numpy/numpy/issues/3290
>
> You need to be a bit more specific, what parts should be yanked out?

It's pretty well discussed in issue 3290 -- but what I'm suggesting is
essentially to ignore time zones completely -- i.e. make the
datetime64 "naive" with respect to time zones.

In fact, it already is -- the only timezone handling it has is that if
it parses an ISO string and no timezone is specified, it applies the
Locale time zone -- this is pretty broken behavior. At the moment, I
can't recall what it does with a datetime.datetime instance, but it's
not quite consitent with what it does parsing string.

I _think_ the only point of contention in that issue 3290 discussion
is how datetime64 should parse and ISO string that provides an offset:

1) ignore it -- probably a bad idea
2) raise an error -- you can't do it.
3) apply the offset so that the resulting datetime64 is assumed to be UTC.

Personally, I think (2) is the way to go, with the possible addition
of allowing zero offset, 'cause, why not?

> I'm
> also worried about breaking peoples' work arounds this late in the game.

well, that is an issue -- though I think most work-arounds will not be
broken, and the discussion about this didn't reveal a single user that
actually used the "use the Locale time zone" feature -- granted,
people contributing to the discussion is a pretty small subset of
users.

But in 1.7 datetime64 is officially experimental, and keeping a broken
implementation around longer will only make for more broken code
later.

-Chris



-- 

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
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Chris.Barker@noaa.gov


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