issue_comments: 155598016

I realize now that changing the internal representation for DataArray doesn't mean we need to rewrite how every routine works. We can still convert dataarrays to a dataset when convenient -- it just means we'll need to use a method to do so instead of modifying ._dataset. For example, we currently have:

python def copy(self, deep=True): ds = self._dataset.copy(deep=deep) return self._with_replaced_dataset(ds)

and instead we could simply write:

python def copy(self, deep=True): ds = self._to_temp_dataset().copy(deep=deep) return self._new_from_temp_dataset(ds)

However, going forward it will give us more flexibility for how to write DataArray methods. For example, it might actually be clearer to write:

python def copy(self, deep=True): variable = self.variable.copy(deep=deep) coords = OrderedDict((k, v.copy(deep=deep)) for k, v in self._coords.items()) return type(self)(variable, coords, name=name, fastpath=True)