share some dtype properties

pandas-dev · jreback · Sep 30, 2020 · May 15, 2020 · May 22, 2020 · May 22, 2020
commit 65a2060eb42fee7c5c4e9050c621473ae4ee7236
diff --git a/pandas/core/arrays/boolean.py b/pandas/core/arrays/boolean.py
@@ -59,7 +59,7 @@ class BooleanDtype(BaseMaskedDtype):
     name = "boolean"
 
     @property
-    def type(self) -> Type[np.bool_]:
+    def type(self) -> Type:
         return np.bool_
 
     @property

diff --git a/pandas/core/arrays/floating.py b/pandas/core/arrays/floating.py
@@ -47,31 +47,13 @@ class FloatingDtype(BaseMaskedDtype):
     The attributes name & type are set when these subclasses are created.
     """
 
-    name: str
-    base = None
-    type: Type
-
     def __repr__(self) -> str:
         return f"{self.name}Dtype()"
 
     @property
     def _is_numeric(self) -> bool:
         return True
 
-    @cache_readonly
-    def numpy_dtype(self) -> np.dtype:
-        """ Return an instance of our numpy dtype """
-        return np.dtype(self.type)
-
-    @cache_readonly
-    def kind(self) -> str:
-        return self.numpy_dtype.kind
-
-    @cache_readonly
-    def itemsize(self) -> int:
-        """ Return the number of bytes in this dtype """
-        return self.numpy_dtype.itemsize
-
     @classmethod
     def construct_array_type(cls) -> Type["FloatingArray"]:
         """

diff --git a/pandas/core/arrays/integer.py b/pandas/core/arrays/integer.py
@@ -46,10 +46,6 @@ class _IntegerDtype(BaseMaskedDtype):
     The attributes name & type are set when these subclasses are created.
     """
 
-    name: str
-    base = None
-    type: Type
-
     def __repr__(self) -> str:
         sign = "U" if self.is_unsigned_integer else ""
         return f"{sign}Int{8 * self.itemsize}Dtype()"
@@ -66,20 +62,6 @@ def is_unsigned_integer(self) -> bool:
     def _is_numeric(self) -> bool:
         return True
 
-    @cache_readonly
-    def numpy_dtype(self) -> np.dtype:
-        """ Return an instance of our numpy dtype """
-        return np.dtype(self.type)
-
-    @cache_readonly
-    def kind(self) -> str:
-        return self.numpy_dtype.kind
-
-    @cache_readonly
-    def itemsize(self) -> int:
-        """ Return the number of bytes in this dtype """
-        return self.numpy_dtype.itemsize
-
     @classmethod
     def construct_array_type(cls) -> Type["IntegerArray"]:
         """

diff --git a/pandas/core/arrays/masked.py b/pandas/core/arrays/masked.py
@@ -5,7 +5,7 @@
 from pandas._libs import lib, missing as libmissing
 from pandas._typing import Scalar
 from pandas.errors import AbstractMethodError
-from pandas.util._decorators import doc
+from pandas.util._decorators import cache_readonly, doc
 
 from pandas.core.dtypes.base import ExtensionDtype
 from pandas.core.dtypes.common import (
@@ -34,11 +34,25 @@ class BaseMaskedDtype(ExtensionDtype):
     Base class for dtypes for BasedMaskedArray subclasses.
     """
 
+    name: str
+    base = None
+    type: Type
+
     na_value = libmissing.NA
 
-    @property
+    @cache_readonly
     def numpy_dtype(self) -> np.dtype:
-        raise AbstractMethodError
+        """ Return an instance of our numpy dtype """
+        return np.dtype(self.type)
+
+    @cache_readonly
+    def kind(self) -> str:
+        return self.numpy_dtype.kind
+
+    @cache_readonly
+    def itemsize(self) -> int:
+        """ Return the number of bytes in this dtype """
+        return self.numpy_dtype.itemsize
 
     @classmethod
     def construct_array_type(cls) -> Type["BaseMaskedArray"]: