bpo-34903: Document that some strptime formats only require 1 digit (GH-14149)
For datetime.datetime.strptime(), the leading zero for some two-digit formats is optional.
This adds a footnote to the strftime/strptime documentation to reflect this fact, and adds some tests to ensure that it is true.
bpo-34903
diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst
index fb41aee..c935e35 100644
--- a/Doc/library/datetime.rst
+++ b/Doc/library/datetime.rst
@@ -2093,7 +2093,7 @@
| | where 0 is Sunday and 6 is | | |
| | Saturday. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%d`` | Day of the month as a | 01, 02, ..., 31 | |
+| ``%d`` | Day of the month as a | 01, 02, ..., 31 | \(9) |
| | zero-padded decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
| ``%b`` | Month as locale's abbreviated || Jan, Feb, ..., Dec | \(1) |
@@ -2106,29 +2106,29 @@
| | || Januar, Februar, ..., | |
| | | Dezember (de_DE) | |
+-----------+--------------------------------+------------------------+-------+
-| ``%m`` | Month as a zero-padded | 01, 02, ..., 12 | |
+| ``%m`` | Month as a zero-padded | 01, 02, ..., 12 | \(9) |
| | decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%y`` | Year without century as a | 00, 01, ..., 99 | |
+| ``%y`` | Year without century as a | 00, 01, ..., 99 | \(9) |
| | zero-padded decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
| ``%Y`` | Year with century as a decimal | 0001, 0002, ..., 2013, | \(2) |
| | number. | 2014, ..., 9998, 9999 | |
+-----------+--------------------------------+------------------------+-------+
-| ``%H`` | Hour (24-hour clock) as a | 00, 01, ..., 23 | |
+| ``%H`` | Hour (24-hour clock) as a | 00, 01, ..., 23 | \(9) |
| | zero-padded decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%I`` | Hour (12-hour clock) as a | 01, 02, ..., 12 | |
+| ``%I`` | Hour (12-hour clock) as a | 01, 02, ..., 12 | \(9) |
| | zero-padded decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
| ``%p`` | Locale's equivalent of either || AM, PM (en_US); | \(1), |
| | AM or PM. || am, pm (de_DE) | \(3) |
+-----------+--------------------------------+------------------------+-------+
-| ``%M`` | Minute as a zero-padded | 00, 01, ..., 59 | |
+| ``%M`` | Minute as a zero-padded | 00, 01, ..., 59 | \(9) |
| | decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%S`` | Second as a zero-padded | 00, 01, ..., 59 | \(4) |
-| | decimal number. | | |
+| ``%S`` | Second as a zero-padded | 00, 01, ..., 59 | \(4), |
+| | decimal number. | | \(9) |
+-----------+--------------------------------+------------------------+-------+
| ``%f`` | Microsecond as a decimal | 000000, 000001, ..., | \(5) |
| | number, zero-padded on the | 999999 | |
@@ -2142,19 +2142,19 @@
| ``%Z`` | Time zone name (empty string | (empty), UTC, EST, CST | |
| | if the object is naive). | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%j`` | Day of the year as a | 001, 002, ..., 366 | |
+| ``%j`` | Day of the year as a | 001, 002, ..., 366 | \(9) |
| | zero-padded decimal number. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%U`` | Week number of the year | 00, 01, ..., 53 | \(7) |
-| | (Sunday as the first day of | | |
+| ``%U`` | Week number of the year | 00, 01, ..., 53 | \(7), |
+| | (Sunday as the first day of | | \(9) |
| | the week) as a zero padded | | |
| | decimal number. All days in a | | |
| | new year preceding the first | | |
| | Sunday are considered to be in | | |
| | week 0. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%W`` | Week number of the year | 00, 01, ..., 53 | \(7) |
-| | (Monday as the first day of | | |
+| ``%W`` | Week number of the year | 00, 01, ..., 53 | \(7), |
+| | (Monday as the first day of | | \(9) |
| | the week) as a decimal number. | | |
| | All days in a new year | | |
| | preceding the first Monday | | |
@@ -2194,8 +2194,8 @@
| ``%u`` | ISO 8601 weekday as a decimal | 1, 2, ..., 7 | |
| | number where 1 is Monday. | | |
+-----------+--------------------------------+------------------------+-------+
-| ``%V`` | ISO 8601 week as a decimal | 01, 02, ..., 53 | \(8) |
-| | number with Monday as | | |
+| ``%V`` | ISO 8601 week as a decimal | 01, 02, ..., 53 | \(8), |
+| | number with Monday as | | \(9) |
| | the first day of the week. | | |
| | Week 01 is the week containing | | |
| | Jan 4. | | |
@@ -2291,6 +2291,11 @@
:meth:`strptime` format string. Also note that ``%G`` and ``%Y`` are not
interchangeable.
+(9)
+ When used with the :meth:`strptime` method, the leading zero is optional
+ for formats ``%d``, ``%m``, ``%H``, ``%I``, ``%M``, ``%S``, ``%J``, ``%U``,
+ ``%W``, and ``%V``. Format ``%y`` does require a leading zero.
+
.. rubric:: Footnotes
.. [#] If, that is, we ignore the effects of Relativity