Module:Date/doc

This module provides date functions for use by other modules. Dates in the Gregorian calendar and the Julian calendar are supported, from 9999 BCE to 9999 CE. The calendars are proleptic—they are assumed to apply at all times with no irregularities.

A date, with an optional time, can be specified in a variety of formats, and can be converted for display using a variety of formats, for example, 1 April 2016 or April 1, 2016. The properties of a date include its Julian date and its Gregorian serial date, as well as the day-of-week and day-of-year.

Dates can be compared (for example, date1 <= date2), and can be used with add or subtract (for example, date + '3 months'). The difference between two dates can be determined with date1 - date2. These operations work with both Gregorian and Julian calendar dates, but date1 - date2 is nil if the two dates use different calendars.

The module provides the following items.

Export	Description
_current	Table with the current year, month, day, hour, minute, second.
_Date	Function that returns a table for a specified date.
_days_in_month	Function that returns the number of days in a month.

The following has examples of using the module:

• Module:Date/example • Demonstration showing how Module:Date may be used.
• Module talk:Date/example • Output from the demonstration.

Formatted output

A date can be formatted as text.

local text = Date(2016, 7, 1):text()          -- result is '1 July 2016'
local text = Date(2016, 7, 1):text('%-d %B')  -- result is '1 July'
local text = Date('1 July 2016'):text('mdy')  -- result is 'July 1, 2016'

The following simplified formatting codes are available.

Code	Result
hm	hour:minute, with "am" or "pm" or variant, if specified (14:30 or 2:30 pm or variant)
hms	hour:minute:second (14:30:45)
ymd	year-month-day (2016-07-01)
mdy	month day, year (July 1, 2016)
dmy	day month year (1 July 2016)

The following formatting codes (similar to strftime) are available.

Code	Result
%a	Day abbreviation: Mon, Tue, ...
%A	Day name: Monday, Tuesday, ...
%u	Day of week: 1 to 7 (Monday to Sunday)
%w	Day of week: 0 to 6 (Sunday to Saturday)
%d	Day of month zero-padded: 01 to 31
%b	Month abbreviation: Jan to Dec
%B	Month name: January to December
%m	Month zero-padded: 01 to 12
%Y	Year zero-padded: 0012, 0120, 1200
%H	Hour 24-hour clock zero-padded: 00 to 23
%I	Hour 12-hour clock zero-padded: 01 to 12
%p	AM or PM or as in options
%M	Minute zero-padded: 00 to 59
%S	Second zero-padded: 00 to 59
%j	Day of year zero-padded: 001 to 366
%-d	Day of month: 1 to 31
%-m	Month: 1 to 12
%-Y	Year: 12, 120, 1200
%-H	Hour: 0 to 23
%-M	Minute: 0 to 59
%-S	Second: 0 to 59
%-j	Day of year: 1 to 366
%-I	Hour: 1 to 12
%%	%

In addition, %{property} (where property is any property of a date) can be used.

For example, Date('1 Feb 2015 14:30:45 A.D.') has the following properties.

Code	Result
%{calendar}	Gregorian
%{year}	2015
%{month}	2
%{day}	1
%{hour}	14
%{minute}	30
%{second}	45
%{dayabbr}	Sun
%{dayname}	Sunday
%{dayofweek}	0
%{dow}	0 (same as dayofweek)
%{dayofweekiso}	7
%{dowiso}	7 (same as dayofweekiso)
%{dayofyear}	32
%{era}	A.D.
%{gsd}	735630 (numbers of days from 1 January 1 CE; the first is day 1)
%{juliandate}	2457055.1046875 (Julian day)
%{jd}	2457055.1046875 (same as juliandate)
%{isleapyear}	false
%{monthdays}	28
%{monthabbr}	Feb
%{monthname}	February

Some shortcuts are available. Given date = Date('1 Feb 2015 14:30'), the following results would occur.

Code	Description	Example result	Equivalent format
date:text('%c')	date and time	2:30 pm 1 February 2015	%-I:%M %p %-d %B %-Y %{era}
date:text('%x')	date	1 February 2015	%-d %B %-Y %{era}
date:text('%X')	time	2:30 pm	%-I:%M %p