On Tue, Mar 1, 2011 at 8:51 AM, Wes McKinney <[email protected]> wrote:
> On Mon, Feb 28, 2011 at 10:52 PM, Wes McKinney <[email protected]> > wrote: > > On Mon, Feb 28, 2011 at 7:24 PM, Pierre GM <[email protected]> wrote: > >> > >> On Mar 1, 2011, at 1:05 AM, Bruce Southey wrote: > >> > >>> On Mon, Feb 28, 2011 at 4:52 PM, Wes McKinney <[email protected]> > wrote: > >>>> I'm having some trouble with the zeros_like function via np.fix: > >>>> > >>>> def zeros_like(a): > >>>> if isinstance(a, ndarray): > >>>> res = ndarray.__new__(type(a), a.shape, a.dtype, > order=a.flags.fnc) > >>>> res.fill(0) > >>>> return res > >>>> try: > >>>> wrap = a.__array_wrap__ > >>>> except AttributeError: > >>>> wrap = None > >>>> a = asarray(a) > >>>> res = zeros(a.shape, a.dtype) > >>>> if wrap: > >>>> res = wrap(res) > >>>> return res > >>>> > >>>> As you can see this is going to discard any metadata stored in a > >>>> subtype. I'm not sure whether this is a bug or a feature but wanted to > >>>> bring it up. > >>>> > >>>> Thanks, > >>>> Wes > >>>> _______________________________________________ > >>>> NumPy-Discussion mailing list > >>>> [email protected] > >>>> http://mail.scipy.org/mailman/listinfo/numpy-discussion > >>>> > >>> > >>> I guess this is ticket 929. > >>> http://projects.scipy.org/numpy/ticket/929 > >>> > >>> I was looking at it today but was not sure what is really desired > >>> here. I considered that this just meant shape and dtype but not sure > >>> about masked or record arrays behavior. So: > >>> What is the value of having the metadata? > >>> What is the meaning of 'like' here? > >> > >> Well, that depends on what you wanna do, of course. To handle metadata, > I use some kind of dictionary updated in the __array_finalize__. Check > numpy.ma.MaskedArray and its subclasses (like scikits.timeseries.TimeSeries) > for the details. > >> Now that you could store some extra data in the dtype (if I remmbr and > understand correctly), it might be worth considering a proper way to deal > with that. > >> > >> > >> _______________________________________________ > >> NumPy-Discussion mailing list > >> [email protected] > >> http://mail.scipy.org/mailman/listinfo/numpy-discussion > >> > > > > The ticket is exactly related to the problem at hand-- having > > __array_finalize__ defined won't help you as it never gets called. > > > > Looks like this commit fixed the problem, so the ticket can be closed > > > https://github.com/numpy/numpy/commit/c9d1849332ae5bf73299ea1268f6a55f78624688#numpy/core/numeric.py > ______ > I've closed the ticket. Chuck
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