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Diffstat (limited to 'Doc/library/datetime.rst')
| -rw-r--r-- | Doc/library/datetime.rst | 152 |
1 files changed, 133 insertions, 19 deletions
diff --git a/Doc/library/datetime.rst b/Doc/library/datetime.rst index 9254ae8..a286fbe 100644 --- a/Doc/library/datetime.rst +++ b/Doc/library/datetime.rst @@ -610,7 +610,8 @@ Instance methods: .. method:: date.__format__(format) Same as :meth:`.date.strftime`. This makes it possible to specify a format - string for a :class:`.date` object when using :meth:`str.format`. For a + string for a :class:`.date` object in :ref:`formatted string + literals <f-strings>` and when using :meth:`str.format`. For a complete list of formatting directives, see :ref:`strftime-strptime-behavior`. @@ -793,16 +794,23 @@ Other constructors, all class methods: microsecond of the result are all 0, and :attr:`.tzinfo` is ``None``. -.. classmethod:: datetime.combine(date, time) +.. classmethod:: datetime.combine(date, time[, tzinfo]) Return a new :class:`.datetime` object whose date components are equal to the - given :class:`date` object's, and whose time components and :attr:`.tzinfo` - attributes are equal to the given :class:`.time` object's. For any - :class:`.datetime` object *d*, - ``d == datetime.combine(d.date(), d.timetz())``. If date is a + given :class:`date` object's, and whose time components + are equal to the given :class:`.time` object's. If the *tzinfo* + argument is provided, its value is used to set the :attr:`.tzinfo` attribute + of the result, otherwise the :attr:`~.time.tzinfo` attribute of the *time* argument + is used. + + For any :class:`.datetime` object *d*, + ``d == datetime.combine(d.date(), d.time(), d.tzinfo)``. If date is a :class:`.datetime` object, its time components and :attr:`.tzinfo` attributes are ignored. + .. versionchanged:: 3.6 + Added the *tzinfo* argument. + .. classmethod:: datetime.strptime(date_string, format) @@ -1138,7 +1146,7 @@ Instance methods: ``self.date().isocalendar()``. -.. method:: datetime.isoformat(sep='T') +.. method:: datetime.isoformat(sep='T', timespec='auto') Return a string representing the date and time in ISO 8601 format, YYYY-MM-DDTHH:MM:SS.mmmmmm or, if :attr:`microsecond` is 0, @@ -1159,6 +1167,37 @@ Instance methods: >>> datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ') '2002-12-25 00:00:00-06:39' + The optional argument *timespec* specifies the number of additional + components of the time to include (the default is ``'auto'``). + It can be one of the following: + + - ``'auto'``: Same as ``'seconds'`` if :attr:`microsecond` is 0, + same as ``'microseconds'`` otherwise. + - ``'hours'``: Include the :attr:`hour` in the two-digit HH format. + - ``'minutes'``: Include :attr:`hour` and :attr:`minute` in HH:MM format. + - ``'seconds'``: Include :attr:`hour`, :attr:`minute`, and :attr:`second` + in HH:MM:SS format. + - ``'milliseconds'``: Include full time, but truncate fractional second + part to milliseconds. HH:MM:SS.sss format. + - ``'microseconds'``: Include full time in HH:MM:SS.mmmmmm format. + + .. note:: + + Excluded time components are truncated, not rounded. + + :exc:`ValueError` will be raised on an invalid *timespec* argument. + + + >>> from datetime import datetime + >>> datetime.now().isoformat(timespec='minutes') + '2002-12-25T00:00' + >>> dt = datetime(2015, 1, 1, 12, 30, 59, 0) + >>> dt.isoformat(timespec='microseconds') + '2015-01-01T12:30:59.000000' + + .. versionadded:: 3.6 + Added the *timespec* argument. + .. method:: datetime.__str__() @@ -1185,7 +1224,8 @@ Instance methods: .. method:: datetime.__format__(format) Same as :meth:`.datetime.strftime`. This makes it possible to specify a format - string for a :class:`.datetime` object when using :meth:`str.format`. For a + string for a :class:`.datetime` object in :ref:`formatted string + literals <f-strings>` and when using :meth:`str.format`. For a complete list of formatting directives, see :ref:`strftime-strptime-behavior`. @@ -1407,13 +1447,46 @@ Instance methods: aware :class:`.time`, without conversion of the time data. -.. method:: time.isoformat() +.. method:: time.isoformat(timespec='auto') Return a string representing the time in ISO 8601 format, HH:MM:SS.mmmmmm or, if - self.microsecond is 0, HH:MM:SS If :meth:`utcoffset` does not return ``None``, a + :attr:`microsecond` is 0, HH:MM:SS If :meth:`utcoffset` does not return ``None``, a 6-character string is appended, giving the UTC offset in (signed) hours and minutes: HH:MM:SS.mmmmmm+HH:MM or, if self.microsecond is 0, HH:MM:SS+HH:MM + The optional argument *timespec* specifies the number of additional + components of the time to include (the default is ``'auto'``). + It can be one of the following: + + - ``'auto'``: Same as ``'seconds'`` if :attr:`microsecond` is 0, + same as ``'microseconds'`` otherwise. + - ``'hours'``: Include the :attr:`hour` in the two-digit HH format. + - ``'minutes'``: Include :attr:`hour` and :attr:`minute` in HH:MM format. + - ``'seconds'``: Include :attr:`hour`, :attr:`minute`, and :attr:`second` + in HH:MM:SS format. + - ``'milliseconds'``: Include full time, but truncate fractional second + part to milliseconds. HH:MM:SS.sss format. + - ``'microseconds'``: Include full time in HH:MM:SS.mmmmmm format. + + .. note:: + + Excluded time components are truncated, not rounded. + + :exc:`ValueError` will be raised on an invalid *timespec* argument. + + + >>> from datetime import time + >>> time(hour=12, minute=34, second=56, microsecond=123456).isoformat(timespec='minutes') + '12:34' + >>> dt = time(hour=12, minute=34, second=56, microsecond=0) + >>> dt.isoformat(timespec='microseconds') + '12:34:56.000000' + >>> dt.isoformat(timespec='auto') + '12:34:56' + + .. versionadded:: 3.6 + Added the *timespec* argument. + .. method:: time.__str__() @@ -1430,7 +1503,8 @@ Instance methods: .. method:: time.__format__(format) Same as :meth:`.time.strftime`. This makes it possible to specify a format string - for a :class:`.time` object when using :meth:`str.format`. For a + for a :class:`.time` object in :ref:`formatted string + literals <f-strings>` and when using :meth:`str.format`. For a complete list of formatting directives, see :ref:`strftime-strptime-behavior`. @@ -1741,10 +1815,7 @@ made to civil time. otherwise :exc:`ValueError` is raised. The *name* argument is optional. If specified it must be a string that - is used as the value returned by the ``tzname(dt)`` method. Otherwise, - ``tzname(dt)`` returns a string 'UTCsHH:MM', where s is the sign of - *offset*, HH and MM are two digits of ``offset.hours`` and - ``offset.minutes`` respectively. + will be used as the value returned by the :meth:`datetime.tzname` method. .. versionadded:: 3.2 @@ -1757,11 +1828,19 @@ made to civil time. .. method:: timezone.tzname(dt) - Return the fixed value specified when the :class:`timezone` instance is - constructed or a string 'UTCsHH:MM', where s is the sign of - *offset*, HH and MM are two digits of ``offset.hours`` and + Return the fixed value specified when the :class:`timezone` instance + is constructed. If *name* is not provided in the constructor, the + name returned by ``tzname(dt)`` is generated from the value of the + ``offset`` as follows. If *offset* is ``timedelta(0)``, the name + is "UTC", otherwise it is a string 'UTC±HH:MM', where ± is the sign + of ``offset``, HH and MM are two digits of ``offset.hours`` and ``offset.minutes`` respectively. + .. versionchanged:: 3.6 + Name generated from ``offset=timedelta(0)`` is now plain 'UTC', not + 'UTC+00:00'. + + .. method:: timezone.dst(dt) Always returns ``None``. @@ -1911,6 +1990,34 @@ format codes. | ``%%`` | A literal ``'%'`` character. | % | | +-----------+--------------------------------+------------------------+-------+ +Several additional directives not required by the C89 standard are included for +convenience. These parameters all correspond to ISO 8601 date values. These +may not be available on all platforms when used with the :meth:`strftime` +method. The ISO 8601 year and ISO 8601 week directives are not interchangeable +with the year and week number directives above. Calling :meth:`strptime` with +incomplete or ambiguous ISO 8601 directives will raise a :exc:`ValueError`. + ++-----------+--------------------------------+------------------------+-------+ +| Directive | Meaning | Example | Notes | ++===========+================================+========================+=======+ +| ``%G`` | ISO 8601 year with century | 0001, 0002, ..., 2013, | \(8) | +| | representing the year that | 2014, ..., 9998, 9999 | | +| | contains the greater part of | | | +| | the ISO week (``%V``). | | | ++-----------+--------------------------------+------------------------+-------+ +| ``%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 | | | +| | the first day of the week. | | | +| | Week 01 is the week containing | | | +| | Jan 4. | | | ++-----------+--------------------------------+------------------------+-------+ + +.. versionadded:: 3.6 + ``%G``, ``%u`` and ``%V`` were added. + Notes: (1) @@ -1975,7 +2082,14 @@ Notes: (7) When used with the :meth:`strptime` method, ``%U`` and ``%W`` are only used - in calculations when the day of the week and the year are specified. + in calculations when the day of the week and the calendar year (``%Y``) + are specified. + +(8) + Similar to ``%U`` and ``%W``, ``%V`` is only used in calculations when the + day of the week and the ISO year (``%G``) are specified in a + :meth:`strptime` format string. Also note that ``%G`` and ``%Y`` are not + interchangeable. .. rubric:: Footnotes |