:right-sidebar: True Date =================================================================== .. currentmodule:: gi.repository.GLib .. class:: Date(**kwargs) :no-contents-entry: ``GDate`` is a struct for calendrical calculations. The ``GDate`` data structure represents a day between January 1, Year 1, and sometime a few thousand years in the future (right now it will go to the year 65535 or so, but :obj:`~gi.repository.GLib.Date.set_parse` only parses up to the year 8000 or so - just count on "a few thousand"). ``GDate`` is meant to represent everyday dates, not astronomical dates or historical dates or ISO timestamps or the like. It extrapolates the current Gregorian calendar forward and backward in time; there is no attempt to change the calendar to match time periods or locations. ``GDate`` does not store time information; it represents a day. The ``GDate`` implementation has several nice features; it is only a 64-bit struct, so storing large numbers of dates is very efficient. It can keep both a Julian and day-month-year representation of the date, since some calculations are much easier with one representation or the other. A Julian representation is simply a count of days since some fixed day in the past; for :obj:`~gi.repository.GLib.Date` the fixed day is January 1, 1 AD. ("Julian" dates in the :obj:`~gi.repository.GLib.Date` API aren't really Julian dates in the technical sense; technically, Julian dates count from the start of the Julian period, Jan 1, 4713 BC). ``GDate`` is simple to use. First you need a "blank" date; you can get a dynamically allocated date from :obj:`~gi.repository.GLib.Date.new`\, or you can declare an automatic variable or array and initialize it by calling :obj:`~gi.repository.GLib.Date.clear`\. A cleared date is safe; it's safe to call :obj:`~gi.repository.GLib.Date.set_dmy` and the other mutator functions to initialize the value of a cleared date. However, a cleared date is initially invalid, meaning that it doesn't represent a day that exists. It is undefined to call any of the date calculation routines on an invalid date. If you obtain a date from a user or other unpredictable source, you should check its validity with the :obj:`~gi.repository.GLib.Date.valid` predicate. :obj:`~gi.repository.GLib.Date.valid` is also used to check for errors with :obj:`~gi.repository.GLib.Date.set_parse` and other functions that can fail. Dates can be invalidated by calling :obj:`~gi.repository.GLib.Date.clear` again. It is very important to use the API to access the ``GDate`` struct. Often only the day-month-year or only the Julian representation is valid. Sometimes neither is valid. Use the API. GLib also features ``GDateTime`` which represents a precise time. Constructors ------------ .. rst-class:: interim-class .. class:: Date :no-index: .. classmethod:: new() -> ~gi.repository.GLib.Date Allocates a :obj:`~gi.repository.GLib.Date` and initializes it to a safe state. The new date will be cleared (as if you'd called :func:`~gi.repository.GLib.Date.clear`) but invalid (it won't represent an existing day). Free the return value with :func:`~gi.repository.GLib.Date.free`. .. classmethod:: new_dmy(day: int, month: ~gi.repository.GLib.DateMonth, year: int) -> ~gi.repository.GLib.Date Create a new :obj:`~gi.repository.GLib.Date` representing the given day-month-year triplet. The triplet you pass in must represent a valid date. Use :func:`~gi.repository.GLib.Date.valid_dmy` if needed to validate it. The returned :obj:`~gi.repository.GLib.Date` is guaranteed to be non-:const:`None` and valid. :param day: day of the month :param month: month of the year :param year: year .. classmethod:: new_julian(julian_day: int) -> ~gi.repository.GLib.Date Create a new :obj:`~gi.repository.GLib.Date` representing the given Julian date. The ``julian_day`` you pass in must be valid. Use :func:`~gi.repository.GLib.Date.valid_julian` if needed to validate it. The returned :obj:`~gi.repository.GLib.Date` is guaranteed to be non-:const:`None` and valid. :param julian_day: days since January 1, Year 1 Methods ------- .. rst-class:: interim-class .. class:: Date :no-index: .. method:: add_days(n_days: int) -> None Increments a date some number of days. To move forward by weeks, add weeks\*7 days. The date must be valid. :param n_days: number of days to move the date forward .. method:: add_months(n_months: int) -> None Increments a date by some number of months. If the day of the month is greater than 28, this routine may change the day of the month (because the destination month may not have the current day in it). The date must be valid. :param n_months: number of months to move forward .. method:: add_years(n_years: int) -> None Increments a date by some number of years. If the date is February 29, and the destination year is not a leap year, the date will be changed to February 28. The date must be valid. :param n_years: number of years to move forward .. method:: clamp(min_date: ~gi.repository.GLib.Date, max_date: ~gi.repository.GLib.Date) -> None If ``date`` is prior to ``min_date``\, sets ``date`` equal to ``min_date``\. If ``date`` falls after ``max_date``\, sets ``date`` equal to ``max_date``\. Otherwise, ``date`` is unchanged. Either of ``min_date`` and ``max_date`` may be :const:`None`. All non-:const:`None` dates must be valid. :param min_date: minimum accepted value for ``date`` :param max_date: maximum accepted value for ``date`` .. method:: clear(n_dates: int) -> None Initializes one or more :obj:`~gi.repository.GLib.Date` structs to a safe but invalid state. The cleared dates will not represent an existing date, but will not contain garbage. Useful to init a date declared on the stack. Validity can be tested with :func:`~gi.repository.GLib.Date.valid`. :param n_dates: number of dates to clear .. method:: compare(rhs: ~gi.repository.GLib.Date) -> int qsort()-style comparison function for dates. Both dates must be valid. :param rhs: second date to compare .. method:: days_between(date2: ~gi.repository.GLib.Date) -> int Computes the number of days between two dates. If ``date2`` is prior to ``date1``\, the returned value is negative. Both dates must be valid. :param date2: the second date .. method:: free() -> None Frees a :obj:`~gi.repository.GLib.Date` returned from :func:`~gi.repository.GLib.Date.new`. .. method:: get_day() -> int Returns the day of the month. The date must be valid. .. method:: get_day_of_year() -> int Returns the day of the year, where Jan 1 is the first day of the year. The date must be valid. .. classmethod:: get_days_in_month(year: int) -> int Returns the number of days in a month, taking leap years into account. :param year: year .. method:: get_iso8601_week_of_year() -> int Returns the week of the year, where weeks are interpreted according to ISO 8601. .. versionadded:: 2.6 .. method:: get_julian() -> int Returns the Julian day or "serial number" of the :obj:`~gi.repository.GLib.Date`\. The Julian day is simply the number of days since January 1, Year 1; i.e., January 1, Year 1 is Julian day 1; January 2, Year 1 is Julian day 2, etc. The date must be valid. .. method:: get_monday_week_of_year() -> int Returns the week of the year, where weeks are understood to start on Monday. If the date is before the first Monday of the year, return 0. The date must be valid. .. classmethod:: get_monday_weeks_in_year() -> int Returns the number of weeks in the year, where weeks are taken to start on Monday. Will be 52 or 53. The date must be valid. (Years always have 52 7-day periods, plus 1 or 2 extra days depending on whether it's a leap year. This function is basically telling you how many Mondays are in the year, i.e. there are 53 Mondays if one of the extra days happens to be a Monday.) .. method:: get_month() -> ~gi.repository.GLib.DateMonth Returns the month of the year. The date must be valid. .. method:: get_sunday_week_of_year() -> int Returns the week of the year during which this date falls, if weeks are understood to begin on Sunday. The date must be valid. Can return 0 if the day is before the first Sunday of the year. .. classmethod:: get_sunday_weeks_in_year() -> int Returns the number of weeks in the year, where weeks are taken to start on Sunday. Will be 52 or 53. The date must be valid. (Years always have 52 7-day periods, plus 1 or 2 extra days depending on whether it's a leap year. This function is basically telling you how many Sundays are in the year, i.e. there are 53 Sundays if one of the extra days happens to be a Sunday.) .. method:: get_weekday() -> ~gi.repository.GLib.DateWeekday Returns the day of the week for a :obj:`~gi.repository.GLib.Date`\. The date must be valid. .. method:: get_year() -> int Returns the year of a :obj:`~gi.repository.GLib.Date`\. The date must be valid. .. method:: is_first_of_month() -> bool Returns :const:`True` if the date is on the first of a month. The date must be valid. .. method:: is_last_of_month() -> bool Returns :const:`True` if the date is the last day of the month. The date must be valid. .. classmethod:: is_leap_year() -> bool Returns :const:`True` if the year is a leap year. For the purposes of this function, leap year is every year divisible by 4 unless that year is divisible by 100. If it is divisible by 100 it would be a leap year only if that year is also divisible by 400. .. method:: order(date2: ~gi.repository.GLib.Date) -> None Checks if ``date1`` is less than or equal to ``date2``\, and swap the values if this is not the case. :param date2: the second date .. method:: set_day(day: int) -> None Sets the day of the month for a :obj:`~gi.repository.GLib.Date`\. If the resulting day-month-year triplet is invalid, the date will be invalid. :param day: day to set .. method:: set_dmy(day: int, month: ~gi.repository.GLib.DateMonth, y: int) -> None Sets the value of a :obj:`~gi.repository.GLib.Date` from a day, month, and year. The day-month-year triplet must be valid; if you aren't sure it is, call :func:`~gi.repository.GLib.Date.valid_dmy` to check before you set it. :param day: day :param month: month :param y: year .. method:: set_julian(julian_date: int) -> None Sets the value of a :obj:`~gi.repository.GLib.Date` from a Julian day number. :param julian_date: Julian day number (days since January 1, Year 1) .. method:: set_month(month: ~gi.repository.GLib.DateMonth) -> None Sets the month of the year for a :obj:`~gi.repository.GLib.Date`\. If the resulting day-month-year triplet is invalid, the date will be invalid. :param month: month to set .. method:: set_parse(str: str) -> None Parses a user-inputted string ``str``\, and try to figure out what date it represents, taking the [current locale][setlocale] into account. If the string is successfully parsed, the date will be valid after the call. Otherwise, it will be invalid. You should check using :func:`~gi.repository.GLib.Date.valid` to see whether the parsing succeeded. This function is not appropriate for file formats and the like; it isn't very precise, and its exact behavior varies with the locale. It's intended to be a heuristic routine that guesses what the user means by a given string (and it does work pretty well in that capacity). :param str: string to parse .. method:: set_time(time_: int) -> None Sets the value of a date from a :obj:`~gi.repository.GLib.Time` value. The time to date conversion is done using the user's current timezone. .. deprecated:: 2.10 Use :func:`~gi.repository.GLib.Date.set_time_t` instead. :param time_: :obj:`~gi.repository.GLib.Time` value to set. .. method:: set_time_t(timet: int) -> None Sets the value of a date to the date corresponding to a time specified as a time_t. The time to date conversion is done using the user's current timezone. To set the value of a date to the current day, you could write: .. code-block:: C :dedent: time_t now = time (NULL); if (now == (time_t) -1) // handle the error g_date_set_time_t (date, now); .. versionadded:: 2.10 :param timet: time_t value to set .. method:: set_time_val(timeval: ~gi.repository.GLib.TimeVal) -> None Sets the value of a date from a :obj:`~gi.repository.GLib.TimeVal` value. Note that the ``tv_usec`` member is ignored, because :obj:`~gi.repository.GLib.Date` can't make use of the additional precision. The time to date conversion is done using the user's current timezone. .. versionadded:: 2.10 .. deprecated:: 2.62 :obj:`~gi.repository.GLib.TimeVal` is not year-2038-safe. Use :func:`~gi.repository.GLib.Date.set_time_t` instead. :param timeval: :obj:`~gi.repository.GLib.TimeVal` value to set .. method:: set_year(year: int) -> None Sets the year for a :obj:`~gi.repository.GLib.Date`\. If the resulting day-month-year triplet is invalid, the date will be invalid. :param year: year to set .. classmethod:: strftime(slen: int, format: str, date: ~gi.repository.GLib.Date) -> int Generates a printed representation of the date, in a [locale][setlocale]-specific way. Works just like the platform's C library strftime() function, but only accepts date-related formats; time-related formats give undefined results. Date must be valid. Unlike strftime() (which uses the locale encoding), works on a UTF-8 format string and stores a UTF-8 result. This function does not provide any conversion specifiers in addition to those implemented by the platform's C library. For example, don't expect that using :func:`~gi.repository.GLib.Date.strftime` would make the \%F provided by the C99 strftime() work on Windows where the C library only complies to C89. :param slen: buffer size :param format: format string :param date: valid :obj:`~gi.repository.GLib.Date` .. method:: subtract_days(n_days: int) -> None Moves a date some number of days into the past. To move by weeks, just move by weeks\*7 days. The date must be valid. :param n_days: number of days to move .. method:: subtract_months(n_months: int) -> None Moves a date some number of months into the past. If the current day of the month doesn't exist in the destination month, the day of the month may change. The date must be valid. :param n_months: number of months to move .. method:: subtract_years(n_years: int) -> None Moves a date some number of years into the past. If the current day doesn't exist in the destination year (i.e. it's February 29 and you move to a non-leap-year) then the day is changed to February 29. The date must be valid. :param n_years: number of years to move .. method:: to_struct_tm(tm: ~typing.Any) -> None Fills in the date-related bits of a struct tm using the ``date`` value. Initializes the non-date parts with something safe but meaningless. :param tm: struct tm to fill .. method:: valid() -> bool Returns :const:`True` if the :obj:`~gi.repository.GLib.Date` represents an existing day. The date must not contain garbage; it should have been initialized with :func:`~gi.repository.GLib.Date.clear` if it wasn't allocated by one of the :func:`~gi.repository.GLib.Date.new` variants. .. classmethod:: valid_day() -> bool Returns :const:`True` if the day of the month is valid (a day is valid if it's between 1 and 31 inclusive). .. classmethod:: valid_dmy(month: ~gi.repository.GLib.DateMonth, year: int) -> bool Returns :const:`True` if the day-month-year triplet forms a valid, existing day in the range of days :obj:`~gi.repository.GLib.Date` understands (Year 1 or later, no more than a few thousand years in the future). :param month: month :param year: year .. classmethod:: valid_julian() -> bool Returns :const:`True` if the Julian day is valid. Anything greater than zero is basically a valid Julian, though there is a 32-bit limit. .. classmethod:: valid_month() -> bool Returns :const:`True` if the month value is valid. The 12 :obj:`~gi.repository.GLib.DateMonth` enumeration values are the only valid months. .. classmethod:: valid_weekday() -> bool Returns :const:`True` if the weekday is valid. The seven :obj:`~gi.repository.GLib.DateWeekday` enumeration values are the only valid weekdays. .. classmethod:: valid_year() -> bool Returns :const:`True` if the year is valid. Any year greater than 0 is valid, though there is a 16-bit limit to what :obj:`~gi.repository.GLib.Date` will understand. Fields ------ .. rst-class:: interim-class .. class:: Date :no-index: .. attribute:: day The day of the day-month-year representation of the date, as a number between 1 and 31 .. attribute:: dmy This is set if ``day``\, ``month`` and ``year`` are valid .. attribute:: julian This bit is set if ``julian_days`` is valid .. attribute:: julian_days The Julian representation of the date .. attribute:: month The month of the day-month-year representation of the date, as a number between 1 and 12 .. attribute:: year The year of the day-month-year representation of the date