[Numpy-discussion] Dates and times and Datetime64 (again)

[Chris Barker]

On Tue, Mar 18, 2014 at 2:49 PM, Sankarshan Mudkavi
<smudkavi at uwaterloo.ca>wrote:

> It's been a while since the last datetime and timezones discussion thread
> was visited (linked below):
>
> http://thread.gmane.org/gmane.comp.python.numeric.general/53805
>
> It looks like the best approach to follow is the UTC only approach in the
> linked thread with an optional flag to indicate the timezone (to avoid
> confusing applications where they don't expect any timezone info). Since
> this is slightly more useful than having just a naive datetime64 package
> and would be open to extension if required, it's probably the best way to
> start improving the datetime64 library.
>

IIUC, I agree -- which is why we need a NEP to specify the details. Thank
you for stepping up!

If we do wish to have full timezone support it would very likely lead to
> performance drops (as reasoned in the thread) and we would need to have a
> dedicated, maintained tzinfo package, at which point it would make much
> more sense to just incorporate the pytz library.
>

yup -- there is the option of doing what the stdlib datetime does --
provide a hook to incorporate timezone,s but don't provide
an implementation, unless that is a low-level hook that must
be implemented in C, it's going to be slow -- slow enough that you might as
well use a list of stdlib datetimes.... Also, this has gone far to long
without getting fixed -- we need something simple to implement more than
anything else.


> I would like to start writing a NEP for this followed by implementation,
> however I'm not sure what the format etc. is, could someone direct me to a
> page where this information is provided?
>

I don't know that there is such a thing, but you'll find the existing NEPS
here:

https://github.com/numpy/numpy/tree/master/doc/neps

I'd grab one and follow the format.


> Please let me know if there are any ideas, comments etc.
>

Thanks again -- I look forward to seeing it written up, -- I'm sure to have
something to say then!

-Chris


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