Improve performance when selecting rows and columns (#53014)

* Improve performance when selecting rows and columns

* Update doc/source/whatsnew/v2.1.0.rst

Co-authored-by: Matthew Roeschke <[email protected]>

* Update indexing.py

* Update v2.1.0.rst

---------

Co-authored-by: Matthew Roeschke <[email protected]>

Author: 2 people

doc/source/whatsnew/v2.1.0.rst

@@ -290,6 +290,7 @@ Performance improvements
 - Performance improvement in :meth:`.DataFrameGroupBy.groups` (:issue:`53088`)
 - Performance improvement in :meth:`DataFrame.loc` when selecting rows and columns (:issue:`53014`)
 - Performance improvement in :meth:`DataFrame.transpose` when transposing a DataFrame with a single masked dtype, e.g. :class:`Int64` (:issue:`52836`)
+- Performance improvement in :meth:`DataFrame.loc` when selecting rows and columns (:issue:`53014`)
 - Performance improvement in :meth:`Series.corr` and :meth:`Series.cov` for extension dtypes (:issue:`52502`)
 - Performance improvement in :meth:`Series.to_numpy` when dtype is a numpy float dtype and ``na_value`` is ``np.nan`` (:issue:`52430`)
 - Performance improvement in :meth:`~arrays.ArrowExtensionArray.to_numpy` (:issue:`52525`)