GLib.Date¶

Fields¶

Name	Type	Access	Description
day	`int`	r/w	the day of the day-month-year representation of the date, as a number between 1 and 31
dmy	`int`	r/w	this is set if day, month and year are valid
julian	`int`	r/w	this bit is set if julian_days is valid
julian_days	`int`	r/w	the Julian representation of the date
month	`int`	r/w	the month of the day-month-year representation of the date, as a number between 1 and 12
year	`int`	r/w	the year of the day-month-year representation of the date

Methods¶

class	`get_days_in_month` (month, year)
class	`get_monday_weeks_in_year` (year)
class	`get_sunday_weeks_in_year` (year)
class	`is_leap_year` (year)
class	`new` ()
class	`new_dmy` (day, month, year)
class	`new_julian` (julian_day)
class	`strftime` (s, slen, format, date)
class	`valid_day` (day)
class	`valid_dmy` (day, month, year)
class	`valid_julian` (julian_date)
class	`valid_month` (month)
class	`valid_weekday` (weekday)
class	`valid_year` (year)
	`add_days` (n_days)
	`add_months` (n_months)
	`add_years` (n_years)
	`clamp` (min_date, max_date)
	`clear` (n_dates)
	`compare` (rhs)
	`copy` ()
	`days_between` (date2)
	`free` ()
	`get_day` ()
	`get_day_of_year` ()
	`get_iso8601_week_of_year` ()
	`get_julian` ()
	`get_monday_week_of_year` ()
	`get_month` ()
	`get_sunday_week_of_year` ()
	`get_weekday` ()
	`get_year` ()
	`is_first_of_month` ()
	`is_last_of_month` ()
	`order` (date2)
	`set_day` (day)
	`set_dmy` (day, month, y)
	`set_julian` (julian_date)
	`set_month` (month)
	`set_parse` (str)
	`set_time` (time_)
	`set_time_t` (timet)
	`set_time_val` (timeval)
	`set_year` (year)
	`subtract_days` (n_days)
	`subtract_months` (n_months)
	`subtract_years` (n_years)
	`to_struct_tm` (tm)
	`valid` ()

Details¶

class GLib.Date¶

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 [method`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 GLib.Date the fixed day is January 1, 1 AD. (“Julian” dates in the 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 [ctor`GLib`.Date.new], or you can declare an automatic variable or array and initialize it by calling [method`GLib`.Date.clear]. A cleared date is safe; it’s safe to call [method`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 [method`GLib`.Date.valid] predicate. [method`GLib`.Date.valid] is also used to check for errors with [method`GLib`.Date.set_parse] and other functions that can fail. Dates can be invalidated by calling [method`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.

classmethod get_days_in_month(month, year)[source]¶

Parameters:

month (GLib.DateMonth) – month
year (int) – year

Returns:

number of days in month during the year

Return type:

int

Returns the number of days in a month, taking leap years into account.

classmethod get_monday_weeks_in_year(year)[source]¶

Parameters:: year (int) – a year
Returns:: number of Mondays in the year
Return type:: 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.)

classmethod get_sunday_weeks_in_year(year)[source]¶

Parameters:: year (int) – year to count weeks in
Returns:: the number of weeks in year
Return type:: 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.)

classmethod is_leap_year(year)[source]¶

Parameters:: year (int) – year to check
Returns:: True if the year is a leap year
Return type:: bool

Returns 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.

classmethod new()[source]¶

Returns:: a newly-allocated GLib.Date
Return type:: GLib.Date

Allocates a GLib.Date and initializes it to a safe state. The new date will be cleared (as if you’d called GLib.Date.clear()) but invalid (it won’t represent an existing day). Free the return value with GLib.Date.free().

classmethod new_dmy(day, month, year)[source]¶

Parameters:

day (int) – day of the month
month (GLib.DateMonth) – month of the year
year (int) – year

Returns:

a newly-allocated GLib.Date initialized with day, month, and year

Return type:

GLib.Date

Create a new GLib.Date representing the given day-month-year triplet.

The triplet you pass in must represent a valid date. Use GLib.Date.valid_dmy() if needed to validate it. The returned GLib.Date is guaranteed to be non-None and valid.

classmethod new_julian(julian_day)[source]¶

Parameters:: julian_day (int) – days since January 1, Year 1
Returns:: a newly-allocated GLib.Date initialized with julian_day
Return type:: GLib.Date

Create a new GLib.Date representing the given Julian date.

The julian_day you pass in must be valid. Use GLib.Date.valid_julian() if needed to validate it. The returned GLib.Date is guaranteed to be non-None and valid.

classmethod strftime(s, slen, format, date)[source]¶

Parameters:

s (str) – destination buffer
slen (int) – buffer size
format (str) – format string
date (GLib.Date) – valid GLib.Date

Returns:

number of characters written to the buffer, or 0 the buffer was too small

Return type:

int

Generates a printed representation of the date, in a locale-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 GLib.Date.strftime() would make the \%F provided by the C99 strftime() work on Windows where the C library only complies to C89.

classmethod valid_day(day)[source]¶

Parameters:: day (int) – day to check
Returns:: True if the day is valid
Return type:: bool

Returns True if the day of the month is valid (a day is valid if it’s between 1 and 31 inclusive).

classmethod valid_dmy(day, month, year)[source]¶

Parameters:

day (int) – day
month (GLib.DateMonth) – month
year (int) – year

Returns:

True if the date is a valid one

Return type:

bool

Returns True if the day-month-year triplet forms a valid, existing day in the range of days GLib.Date understands (Year 1 or later, no more than a few thousand years in the future).

classmethod valid_julian(julian_date)[source]¶

Parameters:: julian_date (int) – Julian day to check
Returns:: True if the Julian day is valid
Return type:: bool

Returns 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(month)[source]¶

Parameters:: month (GLib.DateMonth) – month
Returns:: True if the month is valid
Return type:: bool

Returns True if the month value is valid. The 12 GLib.DateMonth enumeration values are the only valid months.

classmethod valid_weekday(weekday)[source]¶

Parameters:: weekday (GLib.DateWeekday) – weekday
Returns:: True if the weekday is valid
Return type:: bool

Returns True if the weekday is valid. The seven GLib.DateWeekday enumeration values are the only valid weekdays.

classmethod valid_year(year)[source]¶

Parameters:: year (int) – year
Returns:: True if the year is valid
Return type:: bool

Returns True if the year is valid. Any year greater than 0 is valid, though there is a 16-bit limit to what GLib.Date will understand.

add_days(n_days)[source]¶

Parameters:: n_days (int) – number of days to move the date forward

Increments a date some number of days. To move forward by weeks, add weeks*7 days. The date must be valid.

add_months(n_months)[source]¶

Parameters:: n_months (int) – number of months to move forward

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.

add_years(n_years)[source]¶

Parameters:: n_years (int) – number of years to move forward

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.

clamp(min_date, max_date)[source]¶

Parameters:

min_date (GLib.Date) – minimum accepted value for self
max_date (GLib.Date) – maximum accepted value for self

If self is prior to min_date, sets self equal to min_date. If self falls after max_date, sets self equal to max_date. Otherwise, self is unchanged. Either of min_date and max_date may be None. All non-None dates must be valid.

clear(n_dates)[source]¶

Parameters:: n_dates (int) – number of dates to clear

Initializes one or more 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 GLib.Date.valid().

compare(rhs)[source]¶

Parameters:: rhs (GLib.Date) – second date to compare
Returns:: 0 for equal, less than zero if self is less than rhs, greater than zero if self is greater than rhs
Return type:: int

qsort()-style comparison function for dates. Both dates must be valid.

copy()[source]¶

Returns:: a newly-allocated GLib.Date initialized from self
Return type:: GLib.Date

Copies a GLib.Date to a newly-allocated GLib.Date. If the input was invalid (as determined by GLib.Date.valid()), the invalid state will be copied as is into the new object.

New in version 2.56.

days_between(date2)[source]¶

Parameters:: date2 (GLib.Date) – the second date
Returns:: the number of days between self and date2
Return type:: int

Computes the number of days between two dates. If date2 is prior to self, the returned value is negative. Both dates must be valid.

free()[source]¶: Frees a GLib.Date returned from GLib.Date.new().

get_day()[source]¶

Returns:: day of the month
Return type:: int

Returns the day of the month. The date must be valid.

get_day_of_year()[source]¶

Returns:: day of the year
Return type:: int

Returns the day of the year, where Jan 1 is the first day of the year. The date must be valid.

get_iso8601_week_of_year()[source]¶

Returns:: ISO 8601 week number of the year.
Return type:: int

Returns the week of the year, where weeks are interpreted according to ISO 8601.

New in version 2.6.

get_julian()[source]¶

Returns:: Julian day
Return type:: int

Returns the Julian day or “serial number” of the 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.

get_monday_week_of_year()[source]¶

Returns:: week of the year
Return type:: 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.

get_month()[source]¶

Returns:: month of the year as a GLib.DateMonth
Return type:: GLib.DateMonth

Returns the month of the year. The date must be valid.

get_sunday_week_of_year()[source]¶

Returns:: week number
Return type:: 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.

get_weekday()[source]¶

Returns:: day of the week as a GLib.DateWeekday.
Return type:: GLib.DateWeekday

Returns the day of the week for a GLib.Date. The date must be valid.

get_year()[source]¶

Returns:: year in which the date falls
Return type:: int

Returns the year of a GLib.Date. The date must be valid.

is_first_of_month()[source]¶

Returns:: True if the date is the first of the month
Return type:: bool

Returns True if the date is on the first of a month. The date must be valid.

is_last_of_month()[source]¶

Returns:: True if the date is the last day of the month
Return type:: bool

Returns True if the date is the last day of the month. The date must be valid.

order(date2)[source]¶

Parameters:: date2 (GLib.Date) – the second date

Checks if self is less than or equal to date2, and swap the values if this is not the case.

set_day(day)[source]¶

Parameters:: day (int) – day to set

Sets the day of the month for a GLib.Date. If the resulting day-month-year triplet is invalid, the date will be invalid.

set_dmy(day, month, y)[source]¶

Parameters:

day (int) – day
month (GLib.DateMonth) – month
y (int) – year

Sets the value of a GLib.Date from a day, month, and year. The day-month-year triplet must be valid; if you aren’t sure it is, call GLib.Date.valid_dmy() to check before you set it.

set_julian(julian_date)[source]¶

Parameters:: julian_date (int) – Julian day number (days since January 1, Year 1)

Sets the value of a GLib.Date from a Julian day number.

set_month(month)[source]¶

Parameters:: month (GLib.DateMonth) – month to set

Sets the month of the year for a GLib.Date. If the resulting day-month-year triplet is invalid, the date will be invalid.

set_parse(str)[source]¶

Parameters:: str (str) – string to parse

Parses a user-inputted string str, and try to figure out what date it represents, taking the current locale 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 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).

set_time(time_)[source]¶

Parameters:: time (int) – #GTime value to set.

Sets the value of a date from a #GTime value. The time to date conversion is done using the user’s current timezone.

Deprecated since version 2.10: Use GLib.Date.set_time_t() instead.

set_time_t(timet)[source]¶

Parameters:: timet (int) – time_t value to set

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:

time_t now = time (NULL);
if (now == (time_t) -1)
  // handle the error
g_date_set_time_t (date, now);

New in version 2.10.

set_time_val(timeval)[source]¶

Parameters:: timeval (GLib.TimeVal) – GLib.TimeVal value to set

Sets the value of a date from a GLib.TimeVal value. Note that the tv_usec member is ignored, because GLib.Date can’t make use of the additional precision.

The time to date conversion is done using the user’s current timezone.

New in version 2.10.

Deprecated since version 2.62: GLib.TimeVal is not year-2038-safe. Use GLib.Date.set_time_t() instead.

set_year(year)[source]¶

Parameters:: year (int) – year to set

Sets the year for a GLib.Date. If the resulting day-month-year triplet is invalid, the date will be invalid.

subtract_days(n_days)[source]¶

Parameters:: n_days (int) – number of days to move

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.

subtract_months(n_months)[source]¶

Parameters:: n_months (int) – number of months to move

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.

subtract_years(n_years)[source]¶

Parameters:: n_years (int) – number of years to move

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.

to_struct_tm(tm)[source]¶

Parameters:: tm (object) – struct tm to fill

Fills in the date-related bits of a struct tm using the self value. Initializes the non-date parts with something safe but meaningless.

valid()[source]¶

Returns:: Whether the date is valid
Return type:: bool

Returns True if the GLib.Date represents an existing day. The date must not contain garbage; it should have been initialized with GLib.Date.clear() if it wasn’t allocated by one of the GLib.Date.new() variants.