Closes issue #12006: Add ISO 8601 year, week, and day directives to strptime.
This commit adds %G, %V, and %u directives to strptime. Thanks Ashley Anderson for the implementation.
This commit is contained in:
Alexander Belopolsky
parent
fc632e3912
commit
68713e41a5
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@ -1909,6 +1909,34 @@ format codes.
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| ``%%`` | A literal ``'%'`` character. | % | |
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+-----------+--------------------------------+------------------------+-------+
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Several additional directives not required by the C89 standard are included for
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convenience. These parameters all correspond to ISO 8601 date values. These
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may not be available on all platforms when used with the :meth:`strftime`
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method. The ISO 8601 year and ISO 8601 week directives are not interchangeable
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with the year and week number directives above. Calling :meth:`strptime` with
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incomplete or ambiguous ISO 8601 directives will raise a :exc:`ValueError`.
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+-----------+--------------------------------+------------------------+-------+
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| Directive | Meaning | Example | Notes |
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+===========+================================+========================+=======+
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| ``%G`` | ISO 8601 year with century | 0001, 0002, ..., 2013, | \(8) |
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| | representing the year that | 2014, ..., 9998, 9999 | |
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| | contains the greater part of | | |
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| | the ISO week (``%V``). | | |
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+-----------+--------------------------------+------------------------+-------+
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| ``%u`` | ISO 8601 weekday as a decimal | 1, 2, ..., 7 | |
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| | number where 1 is Monday. | | |
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+-----------+--------------------------------+------------------------+-------+
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| ``%V`` | ISO 8601 week as a decimal | 01, 02, ..., 53 | \(8) |
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| | number with Monday as | | |
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| | the first day of the week. | | |
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| | Week 01 is the week containing | | |
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| | Jan 4. | | |
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+-----------+--------------------------------+------------------------+-------+
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.. versionadded:: 3.6
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``%G``, ``%u`` and ``%V`` were added.
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Notes:
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(1)
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@ -1973,7 +2001,14 @@ Notes:
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(7)
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When used with the :meth:`strptime` method, ``%U`` and ``%W`` are only used
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in calculations when the day of the week and the year are specified.
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in calculations when the day of the week and the calendar year (``%Y``)
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are specified.
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(8)
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Similar to ``%U`` and ``%W``, ``%V`` is only used in calculations when the
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day of the week and the ISO year (``%G``) are specified in a
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:meth:`strptime` format string. Also note that ``%G`` and ``%Y`` are not
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interchangable.
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.. rubric:: Footnotes
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@ -110,6 +110,14 @@ Private and special attribute names now are omitted unless the prefix starts
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with underscores. A space or a colon can be added after completed keyword.
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(Contributed by Serhiy Storchaka in :issue:`25011` and :issue:`25209`.)
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datetime
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--------
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* :meth:`datetime.stftime <datetime.datetime.stftime>` and
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:meth:`date.stftime <datetime.date.stftime>` methods now support ISO 8601
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date directives ``%G``, ``%u`` and ``%V``.
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(Contributed by Ashley Anderson in :issue:`12006`.)
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Optimizations
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=============
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@ -195,12 +195,15 @@ class TimeRE(dict):
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'f': r"(?P<f>[0-9]{1,6})",
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'H': r"(?P<H>2[0-3]|[0-1]\d|\d)",
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'I': r"(?P<I>1[0-2]|0[1-9]|[1-9])",
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'G': r"(?P<G>\d\d\d\d)",
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'j': r"(?P<j>36[0-6]|3[0-5]\d|[1-2]\d\d|0[1-9]\d|00[1-9]|[1-9]\d|0[1-9]|[1-9])",
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'm': r"(?P<m>1[0-2]|0[1-9]|[1-9])",
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'M': r"(?P<M>[0-5]\d|\d)",
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'S': r"(?P<S>6[0-1]|[0-5]\d|\d)",
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'U': r"(?P<U>5[0-3]|[0-4]\d|\d)",
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'w': r"(?P<w>[0-6])",
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'u': r"(?P<u>[1-7])",
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'V': r"(?P<V>5[0-3]|0[1-9]|[1-4]\d|\d)",
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# W is set below by using 'U'
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'y': r"(?P<y>\d\d)",
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#XXX: Does 'Y' need to worry about having less or more than
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@ -295,6 +298,22 @@ def _calc_julian_from_U_or_W(year, week_of_year, day_of_week, week_starts_Mon):
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return 1 + days_to_week + day_of_week
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def _calc_julian_from_V(iso_year, iso_week, iso_weekday):
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"""Calculate the Julian day based on the ISO 8601 year, week, and weekday.
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ISO weeks start on Mondays, with week 01 being the week containing 4 Jan.
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ISO week days range from 1 (Monday) to 7 (Sunday).
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"""
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correction = datetime_date(iso_year, 1, 4).isoweekday() + 3
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ordinal = (iso_week * 7) + iso_weekday - correction
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# ordinal may be negative or 0 now, which means the date is in the previous
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# calendar year
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if ordinal < 1:
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ordinal += datetime_date(iso_year, 1, 1).toordinal()
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iso_year -= 1
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ordinal -= datetime_date(iso_year, 1, 1).toordinal()
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return iso_year, ordinal
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def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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"""Return a 2-tuple consisting of a time struct and an int containing
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the number of microseconds based on the input string and the
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@ -339,15 +358,15 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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raise ValueError("unconverted data remains: %s" %
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data_string[found.end():])
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year = None
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iso_year = year = None
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month = day = 1
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hour = minute = second = fraction = 0
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tz = -1
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tzoffset = None
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# Default to -1 to signify that values not known; not critical to have,
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# though
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week_of_year = -1
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week_of_year_start = -1
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iso_week = week_of_year = None
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week_of_year_start = None
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# weekday and julian defaulted to None so as to signal need to calculate
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# values
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weekday = julian = None
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@ -369,6 +388,8 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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year += 1900
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elif group_key == 'Y':
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year = int(found_dict['Y'])
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elif group_key == 'G':
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iso_year = int(found_dict['G'])
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elif group_key == 'm':
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month = int(found_dict['m'])
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elif group_key == 'B':
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@ -414,6 +435,9 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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weekday = 6
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else:
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weekday -= 1
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elif group_key == 'u':
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weekday = int(found_dict['u'])
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weekday -= 1
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elif group_key == 'j':
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julian = int(found_dict['j'])
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elif group_key in ('U', 'W'):
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@ -424,6 +448,8 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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else:
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# W starts week on Monday.
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week_of_year_start = 0
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elif group_key == 'V':
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iso_week = int(found_dict['V'])
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elif group_key == 'z':
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z = found_dict['z']
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tzoffset = int(z[1:3]) * 60 + int(z[3:5])
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@ -444,28 +470,57 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
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else:
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tz = value
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break
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# Deal with the cases where ambiguities arize
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# don't assume default values for ISO week/year
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if year is None and iso_year is not None:
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if iso_week is None or weekday is None:
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raise ValueError("ISO year directive '%G' must be used with "
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"the ISO week directive '%V' and a weekday "
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"directive ('%A', '%a', '%w', or '%u').")
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if julian is not None:
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raise ValueError("Day of the year directive '%j' is not "
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"compatible with ISO year directive '%G'. "
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"Use '%Y' instead.")
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elif week_of_year is None and iso_week is not None:
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if weekday is None:
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raise ValueError("ISO week directive '%V' must be used with "
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"the ISO year directive '%G' and a weekday "
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"directive ('%A', '%a', '%w', or '%u').")
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else:
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raise ValueError("ISO week directive '%V' is incompatible with "
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"the year directive '%Y'. Use the ISO year '%G' "
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"instead.")
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leap_year_fix = False
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if year is None and month == 2 and day == 29:
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year = 1904 # 1904 is first leap year of 20th century
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leap_year_fix = True
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elif year is None:
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year = 1900
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# If we know the week of the year and what day of that week, we can figure
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# out the Julian day of the year.
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if julian is None and week_of_year != -1 and weekday is not None:
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if julian is None and weekday is not None:
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if week_of_year is not None:
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week_starts_Mon = True if week_of_year_start == 0 else False
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julian = _calc_julian_from_U_or_W(year, week_of_year, weekday,
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week_starts_Mon)
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# Cannot pre-calculate datetime_date() since can change in Julian
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# calculation and thus could have different value for the day of the week
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# calculation.
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elif iso_year is not None and iso_week is not None:
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year, julian = _calc_julian_from_V(iso_year, iso_week, weekday + 1)
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if julian is None:
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# Cannot pre-calculate datetime_date() since can change in Julian
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# calculation and thus could have different value for the day of
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# the week calculation.
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# Need to add 1 to result since first day of the year is 1, not 0.
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julian = datetime_date(year, month, day).toordinal() - \
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datetime_date(year, 1, 1).toordinal() + 1
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else: # Assume that if they bothered to include Julian day it will
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# be accurate.
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datetime_result = datetime_date.fromordinal((julian - 1) + datetime_date(year, 1, 1).toordinal())
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else: # Assume that if they bothered to include Julian day (or if it was
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# calculated above with year/week/weekday) it will be accurate.
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datetime_result = datetime_date.fromordinal(
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(julian - 1) +
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datetime_date(year, 1, 1).toordinal())
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year = datetime_result.year
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month = datetime_result.month
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day = datetime_result.day
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@ -152,8 +152,8 @@ class TimeRETests(unittest.TestCase):
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"'%s' using '%s'; group 'a' = '%s', group 'b' = %s'" %
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(found.string, found.re.pattern, found.group('a'),
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found.group('b')))
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for directive in ('a','A','b','B','c','d','H','I','j','m','M','p','S',
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'U','w','W','x','X','y','Y','Z','%'):
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for directive in ('a','A','b','B','c','d','G','H','I','j','m','M','p',
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'S','u','U','V','w','W','x','X','y','Y','Z','%'):
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compiled = self.time_re.compile("%" + directive)
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found = compiled.match(time.strftime("%" + directive))
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self.assertTrue(found, "Matching failed on '%s' using '%s' regex" %
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@ -218,6 +218,26 @@ class StrptimeTests(unittest.TestCase):
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else:
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self.fail("'%s' did not raise ValueError" % bad_format)
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# Ambiguous or incomplete cases using ISO year/week/weekday directives
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# 1. ISO week (%V) is specified, but the year is specified with %Y
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# instead of %G
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with self.assertRaises(ValueError):
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_strptime._strptime("1999 50", "%Y %V")
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# 2. ISO year (%G) and ISO week (%V) are specified, but weekday is not
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with self.assertRaises(ValueError):
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_strptime._strptime("1999 51", "%G %V")
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# 3. ISO year (%G) and weekday are specified, but ISO week (%V) is not
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for w in ('A', 'a', 'w', 'u'):
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with self.assertRaises(ValueError):
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_strptime._strptime("1999 51","%G %{}".format(w))
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# 4. ISO year is specified alone (e.g. time.strptime('2015', '%G'))
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with self.assertRaises(ValueError):
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_strptime._strptime("2015", "%G")
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# 5. Julian/ordinal day (%j) is specified with %G, but not %Y
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with self.assertRaises(ValueError):
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_strptime._strptime("1999 256", "%G %j")
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def test_strptime_exception_context(self):
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# check that this doesn't chain exceptions needlessly (see #17572)
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with self.assertRaises(ValueError) as e:
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@ -289,7 +309,7 @@ class StrptimeTests(unittest.TestCase):
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def test_weekday(self):
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# Test weekday directives
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for directive in ('A', 'a', 'w'):
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for directive in ('A', 'a', 'w', 'u'):
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self.helper(directive,6)
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def test_julian(self):
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@ -458,16 +478,20 @@ class CalculationTests(unittest.TestCase):
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# Should be able to infer date if given year, week of year (%U or %W)
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# and day of the week
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def test_helper(ymd_tuple, test_reason):
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for directive in ('W', 'U'):
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format_string = "%%Y %%%s %%w" % directive
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for year_week_format in ('%Y %W', '%Y %U', '%G %V'):
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for weekday_format in ('%w', '%u', '%a', '%A'):
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format_string = year_week_format + ' ' + weekday_format
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with self.subTest(test_reason,
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date=ymd_tuple,
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format=format_string):
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dt_date = datetime_date(*ymd_tuple)
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strp_input = dt_date.strftime(format_string)
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strp_output = _strptime._strptime_time(strp_input, format_string)
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self.assertTrue(strp_output[:3] == ymd_tuple,
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"%s(%s) test failed w/ '%s': %s != %s (%s != %s)" %
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(test_reason, directive, strp_input,
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strp_output[:3], ymd_tuple,
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strp_output[7], dt_date.timetuple()[7]))
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strp_output = _strptime._strptime_time(strp_input,
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format_string)
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msg = "%r: %s != %s" % (strp_input,
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strp_output[7],
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dt_date.timetuple()[7])
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self.assertEqual(strp_output[:3], ymd_tuple, msg)
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test_helper((1901, 1, 3), "week 0")
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test_helper((1901, 1, 8), "common case")
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test_helper((1901, 1, 13), "day on Sunday")
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@ -499,18 +523,25 @@ class CalculationTests(unittest.TestCase):
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self.assertEqual(_strptime._strptime_time(value, format)[:-1], expected)
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check('2015 0 0', '%Y %U %w', 2014, 12, 28, 0, 0, 0, 6, -3)
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check('2015 0 0', '%Y %W %w', 2015, 1, 4, 0, 0, 0, 6, 4)
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check('2015 1 1', '%G %V %u', 2014, 12, 29, 0, 0, 0, 0, 363)
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check('2015 0 1', '%Y %U %w', 2014, 12, 29, 0, 0, 0, 0, -2)
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check('2015 0 1', '%Y %W %w', 2014, 12, 29, 0, 0, 0, 0, -2)
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check('2015 1 2', '%G %V %u', 2014, 12, 30, 0, 0, 0, 1, 364)
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check('2015 0 2', '%Y %U %w', 2014, 12, 30, 0, 0, 0, 1, -1)
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check('2015 0 2', '%Y %W %w', 2014, 12, 30, 0, 0, 0, 1, -1)
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check('2015 1 3', '%G %V %u', 2014, 12, 31, 0, 0, 0, 2, 365)
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check('2015 0 3', '%Y %U %w', 2014, 12, 31, 0, 0, 0, 2, 0)
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check('2015 0 3', '%Y %W %w', 2014, 12, 31, 0, 0, 0, 2, 0)
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check('2015 1 4', '%G %V %u', 2015, 1, 1, 0, 0, 0, 3, 1)
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check('2015 0 4', '%Y %U %w', 2015, 1, 1, 0, 0, 0, 3, 1)
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check('2015 0 4', '%Y %W %w', 2015, 1, 1, 0, 0, 0, 3, 1)
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check('2015 1 5', '%G %V %u', 2015, 1, 2, 0, 0, 0, 4, 2)
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check('2015 0 5', '%Y %U %w', 2015, 1, 2, 0, 0, 0, 4, 2)
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check('2015 0 5', '%Y %W %w', 2015, 1, 2, 0, 0, 0, 4, 2)
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check('2015 1 6', '%G %V %u', 2015, 1, 3, 0, 0, 0, 5, 3)
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check('2015 0 6', '%Y %U %w', 2015, 1, 3, 0, 0, 0, 5, 3)
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check('2015 0 6', '%Y %W %w', 2015, 1, 3, 0, 0, 0, 5, 3)
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check('2015 1 7', '%G %V %u', 2015, 1, 4, 0, 0, 0, 6, 4)
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class CacheTests(unittest.TestCase):
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