Stream: python-questions

Topic: DataArrary accessor

view this post on Zulip Matt Long (Jun 19 2020 at 03:07):

I am working on an EOF analysis. I find it convenient to write the following "accessor"

@xr.register_dataarray_accessor('eofs')
class eof_analysis(object):
    """perform EOF analysis"""

    def __init__(self, eof_da):
        self._da = eof_da
        self.constituent = eof_da.name

    def compute(self):
        coslat = np.cos(np.deg2rad(self._da.lat.values))
        wgts = np.sqrt(coslat)[..., np.newaxis]

        self.solver = Eof(self._da, center=True, weights=wgts)

        self._ds = xr.merge((
            self.solver.eofs(),
            self.solver.pcs(pcscaling=pcscaling['unit_variance']),
            self.solver.varianceFraction().rename('vf'),
        ))

    def add_reconstruction(self, eof_list):
        recon_name = f'{self.constituent}_'+'_'.join([str(e) for e in eof_list])
        self.ds[recon_name] = self.solver.reconstructedField(eof_list)

    @property
    def ds(self):
        return self._ds

However, in a notebook, I get the following error if this definition is executed more than once:

/glade/work/mclong/miniconda3/envs/co2-hole/lib/python3.7/site-packages/ipykernel_launcher.py:8: AccessorRegistrationWarning: registration of accessor <class '__main__.eof_analysis'> under name 'eofs' for type <class 'xarray.core.dataarray.DataArray'> is overriding a preexisting attribute with the same name.

and the object definition is not updated with edits I might have made. There could be an interaction with "autoload" magic.

Is there a way to "unregister" an accessor?

view this post on Zulip Anderson Banihirwe (Jun 19 2020 at 12:45):

Is there a way to "unregister" an accessor?

You can use delattr on thexr.DataArray class:

try:
     delattr(xr.DataArray, 'eofs')
except AttributeError:
    pass

view this post on Zulip Precious Mongwe (Jun 22 2020 at 17:14):

Sure Deepak, but your link does not work, can you send me the content?, perhaps by email

Last updated: Jan 30 2022 at 12:01 UTC