[Numpy-discussion] An NA compromise idea -- many-NA

[Mark Wiebe]

On Fri, Jul 1, 2011 at 3:32 PM, Charles R Harris
<charlesr.harris at gmail.com>wrote:

> On Fri, Jul 1, 2011 at 1:46 PM, Dag Sverre Seljebotn <
> d.s.seljebotn at astro.uio.no> wrote:
>
>> I propose a simple idea *for the long term* for generalizing Mark's
>> proposal, that I hope may perhaps put some people behind Mark's concrete
>> proposal in the short term.
>>
>> If key feature missing in Mark's proposal is the ability to distinguish
>> between different reason for NA-ness; IGNORE vs. NA. However, one could
>> conceive wanting to track a whole host of reasons:
>>
>> homework_grades = np.asarray([2, 3, 1, EATEN_BY_DOG, 5, SICK, 2,
>> TOO_LAZY])
>>
>> Wouldn't it be a shame to put a lot of work into NA, but then have users
>> to still keep a seperate "shadow-array" for stuff like this?
>>
>> a) In this case the generality of Mark's proposal seems justified and
>> less confusing to teach newcomers (?)
>>
>> b) Since Mark's proposal seems to generalize well to many NAs (there's 8
>> bits in the mask, and millions of available NaN-s in floating point), if
>> people agreed to this one could leave it for later and just go on with
>> the proposed idea.
>>
>>
> Exactly so.
>
>
>> I don't think we should scetch out the above in more detail now, I don't
>> want to distract, I just thought it something to consider to resolve the
>> current situation...
>>
>>
> The important thing is to have a working version to play with, and then see
> how it would be useful to extend it. I think Mark's framework wouldn't
> require a massive rewrite to add this sort of functionality, most of the
> infrastructure would probably remain the same.
>

At the same time, I think it's great to get these ideas out there, because
often it's possible to predict potential future interactions and make minor
course corrections that could save a lot of work later.

-Mark


>
> Chuck
>
>
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