TYPING/DOC: Move custom type to _typing and add whatsnew (#35220)

* remove \n from docstring

* fix issue 17038

* revert change

* revert change

* move defined typing and add whatsnew

Author: charlesdong1991

doc/source/whatsnew/v1.1.0.rst

@@ -332,6 +332,7 @@ Other enhancements
 - :meth:`~Series.explode` now accepts ``ignore_index`` to reset the index, similarly to :meth:`pd.concat` or :meth:`DataFrame.sort_values` (:issue:`34932`).
 - :meth:`read_csv` now accepts string values like "0", "0.0", "1", "1.0" as convertible to the nullable boolean dtype (:issue:`34859`)
 - :class:`pandas.core.window.ExponentialMovingWindow` now supports a ``times`` argument that allows ``mean`` to be calculated with observations spaced by the timestamps in ``times`` (:issue:`34839`)
+- :meth:`DataFrame.agg` and :meth:`Series.agg` now accept named aggregation for renaming the output columns/indexes. (:issue:`26513`)
 
 .. ---------------------------------------------------------------------------
 

pandas/_typing.py

@@ -96,3 +96,11 @@
 # DataFrame::sort_index, among others
 ValueKeyFunc = Optional[Callable[["Series"], Union["Series", AnyArrayLike]]]
 IndexKeyFunc = Optional[Callable[["Index"], Union["Index", AnyArrayLike]]]
+
+# types of `func` kwarg for DataFrame.aggregate and Series.aggregate
+AggFuncTypeBase = Union[Callable, str]
+AggFuncType = Union[
+    AggFuncTypeBase,
+    List[AggFuncTypeBase],
+    Dict[Label, Union[AggFuncTypeBase, List[AggFuncTypeBase]]],
+]

pandas/core/aggregation.py

@@ -17,7 +17,7 @@
     Union,
 )
 
-from pandas._typing import Label
+from pandas._typing import AggFuncType, Label
 
 from pandas.core.dtypes.common import is_dict_like, is_list_like
 
@@ -26,14 +26,6 @@
 from pandas.core.indexes.api import Index
 from pandas.core.series import FrameOrSeriesUnion, Series
 
-# types of `func` kwarg for DataFrame.aggregate and Series.aggregate
-AggFuncTypeBase = Union[Callable, str]
-AggFuncType = Union[
-    AggFuncTypeBase,
-    List[AggFuncTypeBase],
-    Dict[Label, Union[AggFuncTypeBase, List[AggFuncTypeBase]]],
-]
-
 
 def reconstruct_func(
     func: Optional[AggFuncType], **kwargs,