From 3d9d8f6ecc58614fa1ab7579f2ed714bf85ee474 Mon Sep 17 00:00:00 2001
From: Michiel De Muynck <michieldemuynck@gmail.com>
Date: Thu, 7 Nov 2024 17:24:49 +0000
Subject: [PATCH 1/3] Fix issue 50174

---
 pandas/io/excel/_base.py              |  4 ++++
 pandas/tests/io/excel/test_writers.py | 31 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/pandas/io/excel/_base.py b/pandas/io/excel/_base.py
index ef52107c283e9..ced2ad91dba1e 100644
--- a/pandas/io/excel/_base.py
+++ b/pandas/io/excel/_base.py
@@ -8,6 +8,7 @@
     Sequence,
 )
 import datetime
+from decimal import Decimal
 from functools import partial
 import os
 from textwrap import fill
@@ -43,6 +44,7 @@
 
 from pandas.core.dtypes.common import (
     is_bool,
+    is_decimal,
     is_file_like,
     is_float,
     is_integer,
@@ -1348,6 +1350,8 @@ def _value_with_fmt(
             val = float(val)
         elif is_bool(val):
             val = bool(val)
+        elif is_decimal(val):
+            val = Decimal(val)
         elif isinstance(val, datetime.datetime):
             fmt = self._datetime_format
         elif isinstance(val, datetime.date):
diff --git a/pandas/tests/io/excel/test_writers.py b/pandas/tests/io/excel/test_writers.py
index 44266ae9a62a5..acc4caa3cab06 100644
--- a/pandas/tests/io/excel/test_writers.py
+++ b/pandas/tests/io/excel/test_writers.py
@@ -3,6 +3,7 @@
     datetime,
     timedelta,
 )
+from decimal import Decimal
 from functools import partial
 from io import BytesIO
 import os
@@ -977,6 +978,36 @@ def test_to_excel_float_format(self, tmp_excel):
         )
         tm.assert_frame_equal(result, expected)
 
+    def test_to_excel_datatypes_preserved(self, tmp_excel):
+        # Test that when writing and reading Excel with dtype=object,
+        # datatypes are preserved, except Decimals which should be
+        # stored as floats
+
+        # see gh-50174
+        df = DataFrame(
+            [
+                [1.23, "1.23", Decimal("1.23")],
+                [4.56, "4.56", Decimal("4.56")],
+            ],
+            index=["A", "B"],
+            columns=["X", "Y", "Z"],
+        )
+        df.to_excel(tmp_excel)
+
+        with ExcelFile(tmp_excel) as reader:
+            result = pd.read_excel(reader, index_col=0, dtype=object)
+
+        expected = DataFrame(
+            [
+                [1.23, "1.23", 1.23],
+                [4.56, "4.56", 4.56],
+            ],
+            index=["A", "B"],
+            columns=["X", "Y", "Z"],
+            dtype=object,
+        )
+        tm.assert_frame_equal(result, expected)
+
     def test_to_excel_output_encoding(self, tmp_excel):
         # Avoid mixed inferred_type.
         df = DataFrame(

From 023f98f1ca77baf49924a248b9a39dff0227eef0 Mon Sep 17 00:00:00 2001
From: Michiel De Muynck <michieldemuynck@gmail.com>
Date: Thu, 7 Nov 2024 17:41:29 +0000
Subject: [PATCH 2/3] Add release notes

---
 doc/source/whatsnew/v2.3.0.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v2.3.0.rst b/doc/source/whatsnew/v2.3.0.rst
index 922cc0ead7fb0..29bd5f1c8187f 100644
--- a/doc/source/whatsnew/v2.3.0.rst
+++ b/doc/source/whatsnew/v2.3.0.rst
@@ -133,7 +133,7 @@ MultiIndex
 
 I/O
 ^^^
--
+- :meth:`DataFrame.to_excel` was storing decimals as strings instead of numbers (:issue:`50174`)
 -
 
 Period

From 2af69735917930b23bf6ece953a3eb7b560a6ad5 Mon Sep 17 00:00:00 2001
From: Michiel De Muynck <michieldemuynck@gmail.com>
Date: Thu, 7 Nov 2024 17:43:43 +0000
Subject: [PATCH 3/3] Use correct github issue number

---
 doc/source/whatsnew/v2.3.0.rst        | 2 +-
 pandas/tests/io/excel/test_writers.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v2.3.0.rst b/doc/source/whatsnew/v2.3.0.rst
index 29bd5f1c8187f..d57d86f4a1476 100644
--- a/doc/source/whatsnew/v2.3.0.rst
+++ b/doc/source/whatsnew/v2.3.0.rst
@@ -133,7 +133,7 @@ MultiIndex
 
 I/O
 ^^^
-- :meth:`DataFrame.to_excel` was storing decimals as strings instead of numbers (:issue:`50174`)
+- :meth:`DataFrame.to_excel` was storing decimals as strings instead of numbers (:issue:`49598`)
 -
 
 Period
diff --git a/pandas/tests/io/excel/test_writers.py b/pandas/tests/io/excel/test_writers.py
index acc4caa3cab06..81aa0be24bffc 100644
--- a/pandas/tests/io/excel/test_writers.py
+++ b/pandas/tests/io/excel/test_writers.py
@@ -983,7 +983,7 @@ def test_to_excel_datatypes_preserved(self, tmp_excel):
         # datatypes are preserved, except Decimals which should be
         # stored as floats
 
-        # see gh-50174
+        # see gh-49598
         df = DataFrame(
             [
                 [1.23, "1.23", Decimal("1.23")],