add default round method

Author: andrewgsavage

pandas/core/arrays/base.py

@@ -2343,7 +2343,17 @@ def _add_logical_ops(cls) -> None:
         setattr(cls, "__rxor__", cls._create_logical_method(roperator.rxor))
 
     def round(self, decimals: int = 0, *args, **kwargs) -> Self:
-        raise AbstractMethodError(self)
+        # Implementer note: This is a non-optimized default implementation.
+        # Implementers are encouraged to override this method to avoid
+        # elementwise rounding.
+        if not self.dtype._is_numeric or self.dtype._is_boolean:
+            raise TypeError(
+                f"Cannot round {self.dtype} dtype as it is non-numeric or boolean"
+            )
+        return self._from_sequence(
+            [round(element) if not isna(element) else element for element in self.data],
+            dtype=self.dtype,
+        )
 
 
 class ExtensionScalarOpsMixin(ExtensionOpsMixin):

pandas/tests/extension/base/methods.py

@@ -700,11 +700,11 @@ def test_equals_same_data_different_object(self, data):
         assert pd.Series(data).equals(pd.Series(data))
 
     def test_round(self, data):
-        if not data.dtype._is_numeric:
-            pytest.skip("Round is only valid for numeric dtypes")
+        if not data.dtype._is_numeric or data.dtype._is_boolean:
+            pytest.skip("Round is only valid for numeric non-boolean dtypes")
         result = pd.Series(data).round()
         expected = pd.Series(
-            [np.round(element) if pd.notna(element) else element for element in data],
+            [round(element) if pd.notna(element) else element for element in data],
             dtype=data.dtype,
         )
         tm.assert_series_equal(result, expected)

pandas/tests/extension/test_arrow.py

@@ -1017,8 +1017,10 @@ def test_round(self, data, request):
             # raises=pa.ArrowInvalid,
             reason="ArrowArray.round converts dtype to double",
         )
-        if pa.types.is_float32(data.dtype.pyarrow_dtype) or pa.types.is_float64(
-            data.dtype.pyarrow_dtype
+        if (
+            pa.types.is_float32(data.dtype.pyarrow_dtype)
+            or pa.types.is_float64(data.dtype.pyarrow_dtype)
+            or pa.types.is_decimal(data.dtype.pyarrow_dtype)
         ):
             mark = None
         if mark is not None:

pandas/tests/extension/test_interval.py

@@ -89,10 +89,6 @@ def test_EA_types(self, engine, data):
         with pytest.raises(NotImplementedError, match=expected_msg):
             super().test_EA_types(engine, data)
 
-    @pytest.mark.xfail(reason="Round is not valid for IntervalArray.")
-    def test_round(self, data):
-        super().test_round(data)
-
 
 # TODO: either belongs in tests.arrays.interval or move into base tests.
 def test_fillna_non_scalar_raises(data_missing):

pandas/tests/extension/test_masked.py

@@ -359,12 +359,6 @@ def test_invert(self, data, request):
             request.node.add_marker(mark)
         super().test_invert(data)
 
-    def test_round(self, data, request):
-        if data.dtype == "boolean":
-            mark = pytest.mark.xfail(reason="Cannot round boolean dtype")
-            request.node.add_marker(mark)
-        super().test_round(data)
-
 
 class Test2DCompat(base.Dim2CompatTests):
     pass