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
This commit is contained in:
Mike Gleen 2019-06-18 19:14:57 +01:00 committed by Paul Ganssle
parent 59543347d1
commit 6b9c204ee7
3 changed files with 56 additions and 15 deletions

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@ -2093,7 +2093,7 @@ format codes.
| | 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 @@ format codes.
| | || 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 @@ format codes.
| ``%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 @@ incomplete or ambiguous ISO 8601 directives will raise a :exc:`ValueError`.
| ``%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 @@ Notes:
: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