Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

Clarify what changed with respect to date ranges and two-digit years.

This commit is contained in:
Raymond Hettinger 2011-01-21 03:00:00 +00:00
parent 305bc9e0e8
commit f1dae31ea6
1 changed files with 22 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
Doc/whatsnew/3.2.rst
View File

@ -489,8 +489,7 @@ Some smaller changes made to the core Python language are:
original object.
>>> with memoryview(b'abcdefgh') as v:
... print(v.tolist())
...
print(v.tolist())
[97, 98, 99, 100, 101, 102, 103, 104]
(Added by Antoine Pitrou; :issue:`9757`.)
@ -934,20 +933,28 @@ datetime and time
* The :meth:`datetime.date.strftime` method is no longer restricted to years
after 1900. The new supported year range is from 1000 to 9999 inclusive.
* The rules for two-digit years in time tuples have changed. Now, the
:func:`time.asctime`, :func:`time.strftime` and :func:`time.mktime`
functions will accept any two- or four-digit year when
:attr:`time.accept2dyear` is true. Two-digit years are converted to
four-digits using the same heuristics as before, but a deprecation
warning will be issued whenever such conversion occurs.
* Whenever a two-digit year is used in a time tuple, the interpretation has been
governed by :attr:`time.accept2dyear`. The default is *True* which means that
for a two-digit year, the century is guessed according to the POSIX rules
governing the ``%y`` strptime format.
* The :func:`time.asctime`, :func:`time.mktime`, and
:func:`time.strftime` functions are no longer restricted to years
after 1900. Now, when :attr:`time.accept2dyear` is false, the
:func:`time.asctime` function will accept any year that fits in
a C int, while :func:`time.mktime` and :func:`time.strftime`
functions will accept full range supported by the corresponding
operating system functions.
Starting with Py3.2, use of the century guessing heuristic will emit a
:exc:`DeprecationWarning`. Instead, it is recommended that
:attr:`time.accept2dyear` be set to *False* so that large date ranges
can be used without guesswork:
>>> time.accept2dyear = 1 # guess whether 11 means 11 or 2011
>>> time.asctime((11, 1, 1, 12, 34, 56, 4, 1, 0))
'Fri Jan 1 12:34:56 2011'
>>> time.accept2dyear = 0 # use the full range of allowable dates
>>> time.asctime((11, 1, 1, 12, 34, 56, 4, 1, 0))
'Fri Jan 1 12:34:56 11'
Several functions now have significantly expanded date ranges. When
:attr:`time.accept2dyear` is false, the :func:`time.asctime` function will
accept any year that fits in a C int, while the :func:`time.mktime` and
:func:`time.strftime` functions will accept the full range supported by the
corresponding operating system functions.
(Contributed by Alexander Belopolsky and Victor Stinner.)