From 7f77219427103739dc4ae41d23a32dc79305c5a1 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Sun, 30 Apr 2023 16:08:52 +0200
Subject: [PATCH 1/4] Improve performance when selecting rows and columns

---
 doc/source/whatsnew/v2.1.0.rst | 1 +
 pandas/core/indexing.py        | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v2.1.0.rst b/doc/source/whatsnew/v2.1.0.rst
index 988d63db2229f..8f1ebf60eddbb 100644
--- a/doc/source/whatsnew/v2.1.0.rst
+++ b/doc/source/whatsnew/v2.1.0.rst
@@ -286,6 +286,7 @@ Performance improvements
 - 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`)
+- Performance improvement in :meth:`DataFrame.loc` when selecting rows and columns (:issue:`53014)
 -
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 0f1cd397f2dd1..8bfd32b21181b 100644
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -933,7 +933,8 @@ def _getitem_tuple_same_dim(self, tup: tuple):
         This is only called after a failed call to _getitem_lowerdim.
         """
         retval = self.obj
-        for i, key in enumerate(tup):
+        for i, key in enumerate(reversed(tup)):
+            i = self.ndim - i - 1
             if com.is_null_slice(key):
                 continue
 

From 82a011d48033308249c8abff6e012312fd0e3bf7 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Tue, 2 May 2023 23:10:02 +0200
Subject: [PATCH 2/4] Update doc/source/whatsnew/v2.1.0.rst

Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
---
 doc/source/whatsnew/v2.1.0.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v2.1.0.rst b/doc/source/whatsnew/v2.1.0.rst
index 8f1ebf60eddbb..c0a262654aaa4 100644
--- a/doc/source/whatsnew/v2.1.0.rst
+++ b/doc/source/whatsnew/v2.1.0.rst
@@ -286,7 +286,7 @@ Performance improvements
 - 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`)
-- Performance improvement in :meth:`DataFrame.loc` when selecting rows and columns (:issue:`53014)
+- Performance improvement in :meth:`DataFrame.loc` when selecting rows and columns (:issue:`53014`)
 -
 
 .. ---------------------------------------------------------------------------

From abe96ebd45535ce865806a0a2c90ef4d49b7a3f1 Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Tue, 2 May 2023 23:10:51 +0200
Subject: [PATCH 3/4] Update indexing.py

---
 pandas/core/indexing.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 8bfd32b21181b..2a3119515bb99 100644
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -933,6 +933,7 @@ def _getitem_tuple_same_dim(self, tup: tuple):
         This is only called after a failed call to _getitem_lowerdim.
         """
         retval = self.obj
+        # Selecting columns before rows is signficiantly faster
         for i, key in enumerate(reversed(tup)):
             i = self.ndim - i - 1
             if com.is_null_slice(key):

From 01c9eab8352394c29c4790caa8415c7180a0ba3b Mon Sep 17 00:00:00 2001
From: Patrick Hoefler <61934744+phofl@users.noreply.github.com>
Date: Wed, 3 May 2023 23:23:16 +0200
Subject: [PATCH 4/4] Update v2.1.0.rst

---
 doc/source/whatsnew/v2.1.0.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v2.1.0.rst b/doc/source/whatsnew/v2.1.0.rst
index c0a262654aaa4..fa4f4b8cf4b45 100644
--- a/doc/source/whatsnew/v2.1.0.rst
+++ b/doc/source/whatsnew/v2.1.0.rst
@@ -283,10 +283,10 @@ Performance improvements
 - Performance improvement accessing :attr:`arrays.IntegerArrays.dtype` & :attr:`arrays.FloatingArray.dtype` (:issue:`52998`)
 - Performance improvement in :class:`Series` reductions (:issue:`52341`)
 - Performance improvement in :func:`concat` when ``axis=1`` and objects have different indexes (:issue:`52541`)
+- 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`)
-- Performance improvement in :meth:`DataFrame.loc` when selecting rows and columns (:issue:`53014`)
 -
 
 .. ---------------------------------------------------------------------------