CLN: remove methods of ExtensionIndex that duplicate base Index

[jorisvandenbossche]

xref #34159

cc @jbrockmendel

[jorisvandenbossche]

Should be equivalent to

pandas/pandas/core/base.py

Lines 1034 to 1051 in 9c08fe1

	def __iter__(self):
	"""
	Return an iterator of the values.
	These are each a scalar type, which is a Python scalar
	(for str, int, float) or a pandas scalar
	(for Timestamp/Timedelta/Interval/Period)
	Returns
	-------
	iterator
	"""
	# We are explicitly making element iterators.
	if not isinstance(self._values, np.ndarray):
	# Check type instead of dtype to catch DTA/TDA
	return iter(self._values)
	else:
	return map(self._values.item, range(self._values.size))

[jbrockmendel]

Sure (alternatively could remove L1047-1049 from the base class implementation.

[jorisvandenbossche]

alternatively could remove L1047-1049 from the base class implementation

No, because Series also uses that

[jorisvandenbossche]

This is identical with the Index one

[jorisvandenbossche]

The only difference here with the Index one is the use of self._data vs self._values, which as far as I know shouldn't matter?

[jbrockmendel]

not sure if it matters for this method, but the distinction would matter for MultiIndex, which does not have _data.

[jorisvandenbossche]

In this case, MultiIndex actually overrides dropna, so that shouldn't even matter here.

But indeed, in general it's only for MI that using _values vs _data matters, for all the others it's the same (I think?), which I suppose is the reason in the base class there is more usage of _values.

[jorisvandenbossche]

Same here ( self._data vs self._values), and the base class just has an extra if not self._can_hold_na: branch

pandas/pandas/core/indexes/base.py

Lines 688 to 703 in 9c08fe1

	if self._can_hold_na:
	taken = self._assert_take_fillable(
	self._values,
	indices,
	allow_fill=allow_fill,
	fill_value=fill_value,
	na_value=self._na_value,
	)
	else:
	if allow_fill and fill_value is not None:
	cls_name = type(self).__name__
	raise ValueError(
	f"Unable to fill values because {cls_name} cannot contain NA"
	)
	taken = self._values.take(indices)
	return self._shallow_copy(taken)

[jorisvandenbossche]

The base class ends up dispatching to IndexOpsMixin unique:

pandas/pandas/core/base.py

Lines 1257 to 1270 in 9c08fe1

	def unique(self):
	values = self._values
	if hasattr(values, "unique"):
	result = values.unique()
	if self.dtype.kind in ["m", "M"] and isinstance(self, ABCSeries):
	# GH#31182 Series._values returns EA, unpack for backward-compat
	if getattr(self.dtype, "tz", None) is None:
	result = np.asarray(result)
	else:
	result = unique1d(values)
	return result

The hasattr(values, "unique") could probably be made more explicit / cleaner to check for EA, but basically this should also be the same

[jbrockmendel]

could probably be made more explicit / cleaner

sounds worthwhile, yah

[jorisvandenbossche]

@jbrockmendel all good?

[jbrockmendel]

can re-use values here

[jbrockmendel]

all good?

yep