gh-140715: provide support for %F token in strptime; add test for it and %T

Lib/_strptime.py

@@ -418,6 +418,7 @@ def __init__(self, locale_time=None):
         mapping['W'] = mapping['U'].replace('U', 'W')
 
         base.__init__(mapping)
+        base.__setitem__('F', self.pattern('%Y-%m-%d'))
         base.__setitem__('T', self.pattern('%H:%M:%S'))
         base.__setitem__('R', self.pattern('%H:%M'))
         base.__setitem__('r', self.pattern(self.locale_time.LC_time_ampm))

Lib/test/datetimetester.py

@@ -1212,6 +1212,20 @@ def test_strptime_leap_year(self):
             date.strptime('20-03-14', '%y-%m-%d')
             date.strptime('02-29,2024', '%m-%d,%Y')
 
+    def test_strptime_C99_shorthand_year_month_day(self):
+        formats = dict(short="%F",long="%Y-%m-%d")
+        test_date = "2025-10-26"
+        shorthand = datetime.strptime(test_date,formats["short"])
+        long_hand = datetime.strptime(test_date,formats["long"])
+        self.assertEqual(shorthand,long_hand)
+
+    def test_strptime_C99_shorthand_hour_minute_second(self):
+        formats = dict(short="%T",long="%H:%M:%S")
+        test_time = "15:00:00"
+        shorthand = datetime.strptime(test_time,formats["short"])
+        long_hand = datetime.strptime(test_time,formats["long"])
+        self.assertEqual(shorthand,long_hand)
+
 class SubclassDate(date):
     sub_var = 1
 

Lib/test/test_strptime.py

@@ -649,6 +649,22 @@ def test_mar1_comes_after_feb29_even_when_omitting_the_year(self):
                 time.strptime("Feb 29", "%b %d"),
                 time.strptime("Mar 1", "%b %d"))
 
+    def test_shorthand_year_month_day(self):
+        # Test that token '%F' is equivalent to '%Y-%m-%d'
+        formats = dict(short="%F",long="%Y-%m-%d")
+        test_date = "2025-10-26"
+        shorthand = time.strptime(test_date,formats["short"])
+        long_hand = time.strptime(test_date,formats["long"])
+        self.assertEqual(shorthand,long_hand)
+
+    def test_shorthand_hour_minute_second(self):
+        # Test that token '%T' is equivalent to '%H:%M:%S'
+        formats = dict(short="%T",long="%H:%M:%S")
+        test_time = "15:00:00"
+        shorthand = time.strptime(test_time,formats["short"])
+        long_hand = time.strptime(test_time,formats["long"])
+        self.assertEqual(shorthand,long_hand)
+
 class Strptime12AMPMTests(unittest.TestCase):
     """Test a _strptime regression in '%I %p' at 12 noon (12 PM)"""
 

Misc/NEWS.d/next/Library/2025-10-27-00-13-04.gh-issue-140715.WkozE0.rst

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