Custom Dtypes and T

[achapkowski]

I created a custom Array called GeoArray(NumPyBackedExtensionArrayMixin).

When I try to dump out my custom array, I get the following error:

builtins.AttributeError: 'GeoArray' object has no attribute 'T'

What does T have to be? How do I define it?

[TomAugspurger]

When I try to dump out my custom array,

What do you mean dump out?

.T is an alias of .transpose().

[achapkowski]

I mean save the dataframe to an HDF5 table.

[achapkowski]

Where should I define transpose on the on my NumPyBackedExtensionArrayMixin(ExtensionArray): or on my GeoArray class?

[TomAugspurger]

Serializing extensions arrays is basically unsupported right now (though pickle usually works). See #20612, and if you're interested in working on it let us know. It can be done for specific readers / writers in separate PRs.

.T / transpose isn't part of the EA interface and I don't think we'll include it, since it doesn't make sense for EAs.