gh-41431: Add datetime.time.strptime() and datetime.date.strptime()

Doc/library/datetime.rst

@@ -548,6 +548,39 @@ Other constructors, all class methods:
 
  .. versionadded:: 3.8
 
+.. classmethod:: date.strptime(date_string, format)
+
+ Return a :class:`.date` corresponding to *date_string*, parsed according to
+ *format*. This is equivalent to::
+
+ date(*(time.strptime(date_string, format)[0:3]))
+
+ :exc:`ValueError` is raised if the date_string and format
+ can't be parsed by :func:`time.strptime` or if it returns a value which isn't a
+ time tuple. See also :ref:`strftime-strptime-behavior` and
+ :meth:`date.fromisoformat`.
+
+ .. note::
+
+ If *format* specifies a day of month without a year a
+ :exc:`DeprecationWarning` is emitted. This is to avoid a quadrennial
+ leap year bug in code seeking to parse only a month and day as the
+ default year used in absence of one in the format is not a leap year.
+ Such *format* values may raise an error as of Python 3.15. The
+ workaround is to always include a year in your *format*. If parsing
+ *date_string* values that do not have a year, explicitly add a year that
+ is a leap year before parsing:
+
+ .. doctest::
+
+ >>> from datetime import date
+ >>> date_string = "02/29"
+ >>> when = date.strptime(f"{date_string};1984", "%m/%d;%Y") # Avoids leap year bug.
+ >>> when.strftime("%B %d") # doctest: +SKIP
+ 'February 29'
+
+ .. versionadded:: 3.14
+
 
 Class attributes:
 
@@ -1827,7 +1860,7 @@ In Boolean contexts, a :class:`.time` object is always considered to be true.
  details.
 
 
-Other constructor:
+Other constructors:
 
 .. classmethod:: time.fromisoformat(time_string)
 
@@ -1869,6 +1902,22 @@ Other constructor:
  Previously, this method only supported formats that could be emitted by
  :meth:`time.isoformat`.
 
+.. classmethod:: time.strptime(date_string, format)
+
+ Return a :class:`.time` corresponding to *date_string*, parsed according to
+ *format*.
+
+ If *format* does not contain microseconds or timezone information, this is equivalent to::
+
+ time(*(time.strptime(date_string, format)[3:6]))
+
+ :exc:`ValueError` is raised if the *date_string* and *format*
+ cannot be parsed by :func:`time.strptime` or if it returns a value which is not a
+ time tuple. See also :ref:`strftime-strptime-behavior` and
+ :meth:`time.fromisoformat`.
+
+ .. versionadded:: 3.14
+
 
 Instance methods:
 
@@ -2367,24 +2416,22 @@ Class attributes:
 ``strftime(format)`` method, to create a string representing the time under the
 control of an explicit format string.
 
-Conversely, the :meth:`datetime.strptime` class method creates a
-:class:`.datetime` object from a string representing a date and time and a
-corresponding format string.
+Conversely, the :meth:`date.strptime`, :meth:`datetime.strptime` and
+:meth:`time.strptime` class methods create an object from a string
+representing the time and a corresponding format string.
 
 The table below provides a high-level comparison of :meth:`~.datetime.strftime`
 versus :meth:`~.datetime.strptime`:
 
-+----------------+--------------------------------------------------------+------------------------------------------------------------------------------+
-| | ``strftime`` | ``strptime`` |
-+================+========================================================+==============================================================================+
-| Usage | Convert object to a string according to a given format | Parse a string into a :class:`.datetime` object given a corresponding format |
-+----------------+--------------------------------------------------------+------------------------------------------------------------------------------+
-| Type of method | Instance method | Class method |
-+----------------+--------------------------------------------------------+------------------------------------------------------------------------------+
-| Method of | :class:`date`; :class:`.datetime`; :class:`.time` | :class:`.datetime` |
-+----------------+--------------------------------------------------------+------------------------------------------------------------------------------+
-| Signature | ``strftime(format)`` | ``strptime(date_string, format)`` |
-+----------------+--------------------------------------------------------+------------------------------------------------------------------------------+
++----------------+--------------------------------------------------------+------------------------------------------------------------+
+| | ``strftime`` | ``strptime`` |
++================+========================================================+============================================================+
+| Usage | Convert object to a string according to a given format | Parse a string into an object given a corresponding format |
++----------------+--------------------------------------------------------+------------------------------------------------------------+
+| Type of method | Instance method | Class method |
++----------------+--------------------------------------------------------+------------------------------------------------------------+
+| Signature | ``strftime(format)`` | ``strptime(date_string, format)`` |
++----------------+--------------------------------------------------------+------------------------------------------------------------+
 
 
  .. _format-codes:

Doc/whatsnew/3.14.rst

@@ -285,6 +285,12 @@ operator
  (Contributed by Raymond Hettinger and Nico Mexis in :gh:`115808`.)
 
 
+datetime
+--------
+
+Add :meth:`datetime.time.strptime` and :meth:`datetime.date.strptime`.
+(Contributed by Wannes Boeykens in :gh:`41431`.)
+
 os
 --
 

Include/internal/pycore_global_strings.h

@@ -258,7 +258,9 @@ struct _Py_global_strings {
  STRUCT_FOR_ID(_shutdown)
  STRUCT_FOR_ID(_slotnames)
  STRUCT_FOR_ID(_strptime)
- STRUCT_FOR_ID(_strptime_datetime)
+ STRUCT_FOR_ID(_strptime_datetime_date)
+ STRUCT_FOR_ID(_strptime_datetime_datetime)
+ STRUCT_FOR_ID(_strptime_datetime_time)
  STRUCT_FOR_ID(_type_)
  STRUCT_FOR_ID(_uninitialized_submodules)
  STRUCT_FOR_ID(_warn_unawaited_coroutine)

Lib/_pydatetime.py

@@ -940,6 +940,7 @@ class date:
  fromtimestamp()
  today()
  fromordinal()
+ strptime()
 
  Operators:
 
@@ -1040,6 +1041,12 @@ def fromisocalendar(cls, year, week, day):
  This is the inverse of the date.isocalendar() function"""
  return cls(*_isoweek_to_gregorian(year, week, day))
 
+ @classmethod
+ def strptime(cls, date_string, format):
+ """Parse a date string according to the given format (like time.strptime())."""
+ import _strptime
+ return _strptime._strptime_datetime_date(cls, date_string, format)
+
  # Conversions to string
 
  def __repr__(self):
@@ -1360,6 +1367,7 @@ class time:
  Constructors:
 
  __new__()
+ strptime()
 
  Operators:
 
@@ -1418,6 +1426,12 @@ def __new__(cls, hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold
  self._fold = fold
  return self
 
+ @classmethod
+ def strptime(cls, date_string, format):
+ """string, format -> new time parsed from a string (like time.strptime())."""
+ import _strptime
+ return _strptime._strptime_datetime_time(cls, date_string, format)
+
  # Read-only field accessors
  @property
  def hour(self):
@@ -2124,7 +2138,7 @@ def __str__(self):
  def strptime(cls, date_string, format):
  'string, format -> new datetime parsed from a string (like time.strptime()).'
  import _strptime
- return _strptime._strptime_datetime(cls, date_string, format)
+ return _strptime._strptime_datetime_datetime(cls, date_string, format)
 
  def utcoffset(self):
  """Return the timezone offset as timedelta positive east of UTC (negative west of

Lib/_strptime.py

@@ -567,18 +567,40 @@ def _strptime_time(data_string, format="%a %b %d %H:%M:%S %Y"):
  tt = _strptime(data_string, format)[0]
  return time.struct_time(tt[:time._STRUCT_TM_ITEMS])
 
-def _strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
- """Return a class cls instance based on the input string and the
+def _strptime_datetime_date(cls, data_string, format="%a %b %d %Y"):
+ """Return a date instance based on the input string and the
+ format string."""
+ tt, _, _ = _strptime(data_string, format)
+ args = tt[:3]
+ return cls(*args)
+
+def _parse_tz(tzname, gmtoff, gmtoff_fraction):
+ tzdelta = datetime_timedelta(seconds=gmtoff, microseconds=gmtoff_fraction)
+ if tzname:
+ return datetime_timezone(tzdelta, tzname)
+ else:
+ return datetime_timezone(tzdelta)
+
+def _strptime_datetime_time(cls, data_string, format="%H:%M:%S"):
+ """Return a time instance based on the input string and the
  format string."""
  tt, fraction, gmtoff_fraction = _strptime(data_string, format)
  tzname, gmtoff = tt[-2:]
- args = tt[:6] + (fraction,)
- if gmtoff is not None:
- tzdelta = datetime_timedelta(seconds=gmtoff, microseconds=gmtoff_fraction)
- if tzname:
- tz = datetime_timezone(tzdelta, tzname)
- else:
- tz = datetime_timezone(tzdelta)
- args += (tz,)
+ args = tt[3:6] + (fraction,)
+ if gmtoff is None:
+ return cls(*args)
+ else:
+ tz = _parse_tz(tzname, gmtoff, gmtoff_fraction)
+ return cls(*args, tz)
 
- return cls(*args)
+def _strptime_datetime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
+ """Return a datetime instance based on the input string and the
+ format string."""
+ tt, fraction, gmtoff_fraction = _strptime(data_string, format)
+ tzname, gmtoff = tt[-2:]
+ args = tt[:6] + (fraction,)
+ if gmtoff is None:
+ return cls(*args)
+ else:
+ tz = _parse_tz(tzname, gmtoff, gmtoff_fraction)
+ return cls(*args, tz)