[Numpy-discussion] feedback request: proposal to add masks to the core ndarray

[Christopher Barker]

Robert Kern wrote:

> It's worth noting that this is not a replacement for masked arrays,
> nor is it intended to be the be-all, end-all solution to missing data
> problems. It's mostly just intended to be a focused tool to fill in
> the gaps where masked arrays are less convenient for whatever reason;

I think we have enough problems with ndarray vs numpy.ma -- this is 
introducing a third option? IMHO, and from the discussion, it seems this 
proposal should be a "uniter, not a divider".

While masked arrays may still exist, it would be nice if they were an 
extension of the new built-in thingie, not yet another implementation.

>  Not every dtype
> would have an NA-aware counterpart.

One of the great things about numpy is the full range of data types. I 
think it would be surprising and frustrating not to have masked versions 
of them all.

By the way, what might be the performance hit of a "new" dtype -- 
wouldn't we lose all sort of opportunities for the compiler and hardware 
to optimize? I can only image an "if" statement with every single 
computation. But maybe that isn't any more of a hit that a separate mask.

-Chris


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