Re: [Numpy-discussion] adding an attribute to an nd-array

[Stefan v. d. W. <st...@su...>]

On Thu, Oct 19, 2006 at 09:03:57PM -0400, Pierre GM wrote:
> Indeed. That's basically why you have to edit your __array_finalize__ .
>=20
> class InfoArray(N.ndarray):
>     def __new__(info_arr_cls,arr,info=3D{}):
>         info_arr_cls._info =3D info
>         return N.array(arr).view(info_arr_cls)
>     def __array_finalize__(self, obj):
>         if hasattr(obj,'info'):
>             self.info =3D obj.info
>         else:
>             self.info =3D self._info
>         return
>=20
> OK, so you end up w/ two attributes 'info' and '_info', the latter havi=
ng the=20
> info you want, the latter playing a temporary placeholder. That looks a=
 bit=20
> overkill, but that works pretty nice.

Is there any reason why one can't simply do

class InfoArray(N.ndarray):
    def __new__(info_arr_cls,arr,info=3D{}):
        x =3D N.array(arr).view(info_arr_cls)
	x.info =3D info
        return x
    def __array_finalize__(self, obj):
        if hasattr(obj,'info'):
            self.info =3D obj.info
        return

Regards
St=E9fan