pandas-dev#25942 Added ArrayLike and Dtype to pandas._typing

pandas/_typing.py

@@ -1,4 +1,11 @@
 from pathlib import Path
-from typing import IO, AnyStr, Union
+from typing import IO, AnyStr, Type, Union
 
+import numpy as np
+
+from pandas.core.dtypes.dtypes import ExtensionDtype
+from pandas.core.dtypes.generic import ABCExtensionArray
+
+ArrayLike = Union[ABCExtensionArray, np.ndarray]
+Dtype = Union[str, np.dtype, ExtensionDtype, Type]
 FilePathOrBuffer = Union[str, Path, IO[AnyStr]]

pandas/core/arrays/base.py

@@ -21,6 +21,7 @@
     ABCExtensionArray, ABCIndexClass, ABCSeries)
 from pandas.core.dtypes.missing import isna
 
+from pandas._typing import ArrayLike
 from pandas.core import ops
 
 _not_implemented_message = "{} does not implement {}."
@@ -338,7 +339,7 @@ def astype(self, dtype, copy=True):
         """
         return np.array(self, dtype=dtype, copy=copy)
 
-    def isna(self) -> Union[ABCExtensionArray, np.ndarray]:
+    def isna(self) -> ArrayLike:
         """
         A 1-D array indicating if each value is missing.
 

pandas/core/arrays/sparse.py

@@ -4,7 +4,7 @@
 import numbers
 import operator
 import re
-from typing import Any, Callable, Type, Union
+from typing import Any, Callable
 import warnings
 
 import numpy as np
@@ -30,6 +30,7 @@
     ABCIndexClass, ABCSeries, ABCSparseArray, ABCSparseSeries)
 from pandas.core.dtypes.missing import isna, na_value_for_dtype, notna
 
+from pandas._typing import Dtype
 from pandas.core.accessor import PandasDelegate, delegate_names
 import pandas.core.algorithms as algos
 from pandas.core.arrays import ExtensionArray, ExtensionOpsMixin
@@ -79,7 +80,7 @@ class SparseDtype(ExtensionDtype):
 
     def __init__(
             self,
-            dtype: Union[str, np.dtype, ExtensionDtype, Type] = np.float64,
+            dtype: Dtype = np.float64,
             fill_value: Any = None
     ) -> None:
         from pandas.core.dtypes.missing import na_value_for_dtype