REF: share RangeIndex methods (#43952)

Author: jbrockmendel

pandas/core/indexes/base.py

@@ -1027,7 +1027,8 @@ def take(
         taken = algos.take(
             self._values, indices, allow_fill=allow_fill, fill_value=self._na_value
         )
-        return type(self)._simple_new(taken, name=self.name)
+        # _constructor so RangeIndex->Int64Index
+        return self._constructor._simple_new(taken, name=self.name)
 
     @final
     def _maybe_disallow_fill(self, allow_fill: bool, fill_value, indices) -> bool:
@@ -1097,7 +1098,8 @@ def repeat(self, repeats, axis=None):
         nv.validate_repeat((), {"axis": axis})
         res_values = self._values.repeat(repeats)
 
-        return type(self)._simple_new(res_values, name=self.name)
+        # _constructor so RangeIndex->Int64Index
+        return self._constructor._simple_new(res_values, name=self.name)
 
     # --------------------------------------------------------------------
     # Copying Methods
@@ -6298,7 +6300,8 @@ def delete(self: _IndexT, loc) -> _IndexT:
         Index(['b'], dtype='object')
         """
         res_values = np.delete(self._data, loc)
-        return type(self)._simple_new(res_values, name=self.name)
+        # _constructor so RangeIndex->Int64Index
+        return self._constructor._simple_new(res_values, name=self.name)
 
     def insert(self, loc: int, item) -> Index:
         """

pandas/core/indexes/range.py

@@ -26,7 +26,6 @@
     cache_readonly,
     doc,
 )
-from pandas.util._exceptions import rewrite_exception
 
 from pandas.core.dtypes.common import (
     ensure_platform_int,
@@ -189,17 +188,6 @@ def _data(self) -> np.ndarray:
         """
         return np.arange(self.start, self.stop, self.step, dtype=np.int64)
 
-    @cache_readonly
-    def _cached_int64index(self) -> Int64Index:
-        return Int64Index._simple_new(self._data, name=self.name)
-
-    @property
-    def _int64index(self) -> Int64Index:
-        # wrap _cached_int64index so we can be sure its name matches self.name
-        res = self._cached_int64index
-        res._name = self._name
-        return res
-
     def _get_data_as_items(self):
         """return a list of tuples of start, stop, step"""
         rng = self._range
@@ -425,24 +413,6 @@ def _get_indexer(
 
     # --------------------------------------------------------------------
 
-    def repeat(self, repeats, axis=None) -> Int64Index:
-        return self._int64index.repeat(repeats, axis=axis)
-
-    def delete(self, loc) -> Int64Index:  # type: ignore[override]
-        return self._int64index.delete(loc)
-
-    def take(
-        self, indices, axis: int = 0, allow_fill: bool = True, fill_value=None, **kwargs
-    ) -> Int64Index:
-        with rewrite_exception("Int64Index", type(self).__name__):
-            return self._int64index.take(
-                indices,
-                axis=axis,
-                allow_fill=allow_fill,
-                fill_value=fill_value,
-                **kwargs,
-            )
-
     def tolist(self) -> list[int]:
         return list(self._range)
 
@@ -683,7 +653,8 @@ def _union(self, other: Index, sort):
                     and (end_s - step_o <= end_o)
                 ):
                     return type(self)(start_r, end_r + step_o, step_o)
-        return self._int64index._union(other, sort=sort)
+
+        return super()._union(other, sort=sort)
 
     def _difference(self, other, sort=None):
         # optimized set operation if we have another RangeIndex
@@ -857,7 +828,8 @@ def __floordiv__(self, other):
                 start = self.start // other
                 new_range = range(start, start + 1, 1)
                 return self._simple_new(new_range, name=self.name)
-        return self._int64index // other
+
+        return super().__floordiv__(other)
 
     # --------------------------------------------------------------------
     # Reductions
@@ -891,21 +863,22 @@ def _arith_method(self, other, op):
         elif isinstance(other, (timedelta, np.timedelta64)):
             # GH#19333 is_integer evaluated True on timedelta64,
             # so we need to catch these explicitly
-            return op(self._int64index, other)
+            return super()._arith_method(other, op)
         elif is_timedelta64_dtype(other):
             # Must be an np.ndarray; GH#22390
-            return op(self._int64index, other)
+            return super()._arith_method(other, op)
 
         if op in [
             operator.pow,
             ops.rpow,
             operator.mod,
             ops.rmod,
+            operator.floordiv,
             ops.rfloordiv,
             divmod,
             ops.rdivmod,
         ]:
-            return op(self._int64index, other)
+            return super()._arith_method(other, op)
 
         step: Callable | None = None
         if op in [operator.mul, ops.rmul, operator.truediv, ops.rtruediv]:
@@ -946,5 +919,5 @@ def _arith_method(self, other, op):
 
         except (ValueError, TypeError, ZeroDivisionError):
             # Defer to Int64Index implementation
-            return op(self._int64index, other)
-            # TODO: Do attrs get handled reliably?
+            # test_arithmetic_explicit_conversions
+            return super()._arith_method(other, op)

pandas/tests/arithmetic/test_numeric.py

@@ -1311,18 +1311,22 @@ def test_numeric_compat2(self):
         # __pow__
         idx = RangeIndex(0, 1000, 2)
         result = idx ** 2
-        expected = idx._int64index ** 2
+        expected = Int64Index(idx._values) ** 2
         tm.assert_index_equal(Index(result.values), expected, exact=True)
 
         # __floordiv__
         cases_exact = [
             (RangeIndex(0, 1000, 2), 2, RangeIndex(0, 500, 1)),
             (RangeIndex(-99, -201, -3), -3, RangeIndex(33, 67, 1)),
-            (RangeIndex(0, 1000, 1), 2, RangeIndex(0, 1000, 1)._int64index // 2),
+            (
+                RangeIndex(0, 1000, 1),
+                2,
+                Int64Index(RangeIndex(0, 1000, 1)._values) // 2,
+            ),
             (
                 RangeIndex(0, 100, 1),
                 2.0,
-                RangeIndex(0, 100, 1)._int64index // 2.0,
+                Int64Index(RangeIndex(0, 100, 1)._values) // 2.0,
             ),
             (RangeIndex(0), 50, RangeIndex(0)),
             (RangeIndex(2, 4, 2), 3, RangeIndex(0, 1, 1)),

pandas/tests/indexes/ranges/test_range.py

@@ -299,12 +299,12 @@ def test_identical(self, simple_index):
     def test_nbytes(self):
 
         # memory savings vs int index
-        i = RangeIndex(0, 1000)
-        assert i.nbytes < i._int64index.nbytes / 10
+        idx = RangeIndex(0, 1000)
+        assert idx.nbytes < Int64Index(idx.values).nbytes / 10
 
         # constant memory usage
         i2 = RangeIndex(0, 10)
-        assert i.nbytes == i2.nbytes
+        assert idx.nbytes == i2.nbytes
 
     @pytest.mark.parametrize(
         "start,stop,step",

pandas/tests/indexes/ranges/test_setops.py

@@ -286,7 +286,7 @@ def test_union_sorted(self, unions):
         tm.assert_index_equal(res1, expected_notsorted, exact=True)
 
         res2 = idx2.union(idx1, sort=None)
-        res3 = idx1._int64index.union(idx2, sort=None)
+        res3 = Int64Index(idx1._values, name=idx1.name).union(idx2, sort=None)
         tm.assert_index_equal(res2, expected_sorted, exact=True)
         tm.assert_index_equal(res3, expected_sorted)
 
@@ -322,11 +322,11 @@ def test_difference_mismatched_step(self):
         obj = RangeIndex.from_range(range(1, 10), name="foo")
 
         result = obj.difference(obj[::2])
-        expected = obj[1::2]._int64index
+        expected = Int64Index(obj[1::2]._values, name=obj.name)
         tm.assert_index_equal(result, expected, exact=True)
 
         result = obj.difference(obj[1::2])
-        expected = obj[::2]._int64index
+        expected = Int64Index(obj[::2]._values, name=obj.name)
         tm.assert_index_equal(result, expected, exact=True)
 
     def test_symmetric_difference(self):

pandas/tests/reductions/test_reductions.py

@@ -221,15 +221,15 @@ class TestIndexReductions:
     def test_max_min_range(self, start, stop, step):
         # GH#17607
         idx = RangeIndex(start, stop, step)
-        expected = idx._int64index.max()
+        expected = idx._values.max()
         result = idx.max()
         assert result == expected
 
         # skipna should be irrelevant since RangeIndex should never have NAs
         result2 = idx.max(skipna=False)
         assert result2 == expected
 
-        expected = idx._int64index.min()
+        expected = idx._values.min()
         result = idx.min()
         assert result == expected
 
@@ -431,13 +431,11 @@ def test_numpy_minmax_range(self):
         # GH#26125
         idx = RangeIndex(0, 10, 3)
 
-        expected = idx._int64index.max()
         result = np.max(idx)
-        assert result == expected
+        assert result == 9
 
-        expected = idx._int64index.min()
         result = np.min(idx)
-        assert result == expected
+        assert result == 0
 
         errmsg = "the 'out' parameter is not supported"
         with pytest.raises(ValueError, match=errmsg):