[Numpy-discussion] What is consensus anyway

[josef.pktd at gmail.com]

On Tue, Apr 24, 2012 at 9:43 AM, Pierre Haessig
<pierre.haessig at crans.org> wrote:
> Hi,
>
> Le 24/04/2012 15:14, Charles R Harris a écrit :
>>
>> a) All arrays should be implicitly masked, even if the mask isn't
>> initially allocated. The maskna keyword can then be removed, taking
>> with it the sense that there are two kinds of arrays.
>>
>
> From my lazy user perspective, having masked and non-masked arrays share
> the same "look and feel" would be a number one advantage over the
> existing numpy.ma arrays. I would like masked array to be as transparent
> as possible.

I don't have any opinion about internal implementation.

But users needs to be aware of whether they have masked arrays or not.
Since many functions (most of scipy) wouldn't know how to handle NA
and don't do any checks, (and shouldn't in my opinion if the NA check
is costly). The result might be silently wrong numbers depending on
the implementation.

>
>> b) There needs to be a distinction between missing and ignore. The
>> mechanism for this is already in place in the payload type, although
>> it isn't clear to me that that is uniformly used in all the NA code.
>> There is also a place for missing *and* ignored. Which leads to
>
> If the idea of having two payloads is to avoid a maximum of "skipna &
> friends" extra keywords, I would like it much. My feeling with my small
> experience with R is that I end up calling every function with a
> different magical set of keywords (na.rm, na.action, ... and I forgot).

There is a reason for requiring the user to decide what to do about NA's.
Either we have utility functions/methods to help the user change the
arrays and treat NA's before calling a function, or the function needs
to ask the user what should be done about possible NAs.
Doing it automatically might only be useful for specialised packages.

My 2c

Josef

>
> My 2 lazy user cents...
>
> Best,
> Pierre
>
>
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