On Sat, Jun 25, 2011 at 8:31 AM, Matthew Brett <[email protected]>wrote:
> Hi, > > On Sat, Jun 25, 2011 at 3:21 PM, Charles R Harris > <[email protected]> wrote: > > > > > > On Sat, Jun 25, 2011 at 5:29 AM, Pierre GM <[email protected]> wrote: > >> > >> This thread is getting quite long, innit ? > >> And I think it's getting a tad confusing, because we're mixing two > >> different concepts: missing values and masks. > >> There should be support for missing values in numpy.core, I think we all > >> agree on that. > >> * What's been suggested of adding new dtypes (nafloat, naint) is great, > by > >> why not making it the default, then ? > >> > >> * Operations involving a NA (whatever the NA actually is, depending on > the > >> dtype of the input) should result in a NA (whatever the NA defined by > the > >> outputs dtype). That could be done by overloading the existing ufuncs to > >> support the new dtypes. > >> * There should be some simple methods to retrieve the location of those > >> NAs in an array. Whether we just output the indices or a full boolean > array > >> (w/ True for a NA, False for a non-NA or vice-versa) needs to be > decided. > >> * We can always re-implement masked arrays to use these NAs in a way > which > >> would be consistent with numpy.ma (so as not to confuse existing users > of > >> numpy.ma): a mask would be a boolean array with the same shape than the > >> underlying ndarray, with True for NA. > >> Mark, I'd suggest you modify your proposal, making it clearer that it's > >> not to add all of numpy.ma functionalities in the core, but just > support > >> these missing values. Using the term 'mask' should be avoided as much as > >> possible, use a 'missing data' or whatever. > > > > I think he aims to support both. > > I don't think Mark is proposing to support both. He's proposing to > implement only array.mask. > > I think you are confusing function with implementation. If you look at the current NEP, it does NA but does so by using masks behind the scene in a transparent manner. Chuck
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