Fix issues with trailing whitespace and isort

Author: HoqueUM

doc/source/whatsnew/v3.0.0.rst

@@ -70,6 +70,7 @@ Other enhancements
 - :meth:`.DataFrameGroupBy.transform`, :meth:`.SeriesGroupBy.transform`, :meth:`.DataFrameGroupBy.agg`, :meth:`.SeriesGroupBy.agg`, :meth:`.SeriesGroupBy.apply`, :meth:`.DataFrameGroupBy.apply` now support ``kurt`` (:issue:`40139`)
 - :meth:`DataFrame.apply` supports using third-party execution engines like the Bodo.ai JIT compiler (:issue:`60668`)
 - :meth:`DataFrame.iloc` and :meth:`Series.iloc` now support boolean masks in ``__getitem__`` for more consistent indexing behavior (:issue:`60994`)
+- :meth:`Dataframe.select_by_substr` is a new method to select columns by substring, with the option to ignore case (defaulted to true) (:issue:`61319`)
 - :meth:`DataFrameGroupBy.transform`, :meth:`SeriesGroupBy.transform`, :meth:`DataFrameGroupBy.agg`, :meth:`SeriesGroupBy.agg`, :meth:`RollingGroupby.apply`, :meth:`ExpandingGroupby.apply`, :meth:`Rolling.apply`, :meth:`Expanding.apply`, :meth:`DataFrame.apply` with ``engine="numba"`` now supports positional arguments passed as kwargs (:issue:`58995`)
 - :meth:`Rolling.agg`, :meth:`Expanding.agg` and :meth:`ExponentialMovingWindow.agg` now accept :class:`NamedAgg` aggregations through ``**kwargs`` (:issue:`28333`)
 - :meth:`Series.map` can now accept kwargs to pass on to func (:issue:`59814`)

pandas/core/frame.py

@@ -30,11 +30,11 @@
 from typing import (
     TYPE_CHECKING,
     Any,
-    Literal,
     List,
+    Literal,
+    Union,
     cast,
     overload,
-    Union
 )
 import warnings
 
@@ -7718,7 +7718,7 @@ def nsmallest(
         Nauru         337000  182      NR
         """
         return selectn.SelectNFrame(self, n=n, keep=keep, columns=columns).nsmallest()
-    
+
     def select_by_substr(
             self,
             substr: Union[str, List[str]],

pandas/tests/frame/test_select_by_substr.py

@@ -1,7 +1,9 @@
 import pytest
+
 from pandas import DataFrame
 import pandas._testing as tm
 
+
 class TestSelectBySubstr:
     @pytest.fixture
     def df(self):