gh-140715: Add %D format code support to strptime()

Doc/library/datetime.rst

@@ -2534,8 +2534,8 @@ requires, and these work on all supported platforms.
 |  ``%d``   | Day of the month as a          | 01, 02, ..., 31        | \(9)  |
 |           | zero-padded decimal number.    |                        |       |
 +-----------+--------------------------------+------------------------+-------+
-|  ``%D``   | Equivalent to ``%m/%d/%y``.    | 11/10/2025             | \(9), |
-|           |                                |                        | \(0)  |
+|  ``%D``   | Equivalent to ``%m/%d/%y``.    | 11/28/2025             | \(9)  |
+|           |                                |                        |       |
 +-----------+--------------------------------+------------------------+-------+
 |  ``%e``   | The day of the month as a      | ␣1, ␣2, ..., 31        |       |
 |           | space-padded decimal number.   |                        |       |
@@ -2676,7 +2676,7 @@ differences between platforms in handling of unsupported format specifiers.
    ``%:z`` was added for :meth:`~.datetime.strftime`.
 
 .. versionadded:: 3.15
-   ``%:z`` and ``%F`` were added for :meth:`~.datetime.strptime`.
+   ``%:z``, ``%F``, and ``%D`` were added for :meth:`~.datetime.strptime`.
 
 Technical Detail
 ^^^^^^^^^^^^^^^^

Lib/_strptime.py

@@ -425,6 +425,7 @@ def __init__(self, locale_time=None):
         base.__setitem__('X', self.pattern(self.locale_time.LC_time))
         base.__setitem__('x', self.pattern(self.locale_time.LC_date))
         base.__setitem__('c', self.pattern(self.locale_time.LC_date_time))
+        base.__setitem__('D', self.pattern('%m/%d/%Y'))
 
     def __seqToRE(self, to_convert, directive, altregex=None):
         """Convert a list to a regex string for matching a directive.

Lib/test/datetimetester.py

@@ -2200,6 +2200,13 @@ def test_strptime_F_format(self):
             self.theclass.strptime(test_date, "%Y-%m-%d")
         )
 
+    def test_strptime_D_format(self):
+        test_date = "11/28/2025"
+        self.assertEqual(
+            self.theclass.strptime(test_date, "%D"),
+            self.theclass.strptime(test_date, "%m/%d/%Y")
+        )
+
 
 #############################################################################
 # datetime tests

Lib/test/test_strptime.py

@@ -663,6 +663,13 @@ def test_strptime_T_format(self):
             time.strptime(test_time, "%H:%M:%S")
         )
 
+    def test_strptime_D_format(self):
+        test_date = "11/28/2025"
+        self.assertEqual(
+            time.strptime(test_date, "%D"),
+            time.strptime(test_date, "%m/%d/%Y")
+        )
+
 class Strptime12AMPMTests(unittest.TestCase):
     """Test a _strptime regression in '%I %p' at 12 noon (12 PM)"""
 

Misc/NEWS.d/next/Library/2026-02-14-14-56-44.gh-issue-140715.AbSheM.rst

@@ -0,0 +1 @@
+Add ``'%D'`` support to :meth:`~datetime.datetime.strptime`.