This class represents a basic CF calendar. It should not be instantiated directly; instead, use one of the descendant classes.
This internal class stores the information to represent date and time values using the CF conventions. An instance is created by the exported CFTime class, which also exposes the relevant properties of this class.
The following calendars are supported:
gregorian\standard, the international standard calendar for civil use.proleptic_gregorian, the standard calendar but extending before 1582-10-15 when the Gregorian calendar was adopted.tai, International Atomic Time clock with dates expressed using the Gregorian calendar.utc, Coordinated Universal Time clock with dates expressed using the Gregorian calendar.julian, every fourth year is a leap year (so including the years 1700, 1800, 1900, 2100, etc).noleap\365_day, all years have 365 days.all_leap\366_day, all years have 366 days.360_day, all years have 360 days, divided over 12 months of 30 days.
References
https://cfconventions.org/Data/cf-conventions/cf-conventions-1.12/cf-conventions.html#calendar
Public fields
nameDescriptive name of the calendar, as per the CF Metadata Conventions.
definitionThe string that defines the units and the origin, as per the CF Metadata Conventions.
unitThe numeric id of the unit of the calendar.
origindata.framewith fields for the origin of the calendar.
Active bindings
origin_date(read-only) Character string with the date of the calendar.
origin_time(read-only) Character string with the time of the calendar.
timezone(read-only) Character string with the time zone of the origin of the calendar.
Methods
Method print()
Print information about the calendar to the console.
Method valid_days()
Indicate which of the supplied dates are valid.
Method add_day()
Add a day to the supplied dates.
Method POSIX_compatible()
Indicate if the time series described using this calendar
can be safely converted to a standard date-time type (POSIXct,
POSIXlt, Date).
Only the 'standard' calendar and the 'proleptic_gregorian' calendar
when all dates in the time series are more recent than 1582-10-15
(inclusive) can be safely converted, so this method returns FALSE by
default to cover the majority of cases.
Method is_compatible()
This method tests if the CFCalendar instance in argument
cal is compatible with self, meaning that they are of the same
class and have the same unit. Calendars "standard", and "gregorian" are
compatible, as are the pairs of "365_day" and "no_leap", and "366_day"
and "all_leap".
Method is_equivalent()
This method tests if the CFCalendar instance in argument
cal is equivalent to self, meaning that they are of the same class,
have the same unit, and equivalent origins. Calendars "standard", and
"gregorian" are equivalent, as are the pairs of "365_day" and
"no_leap", and "366_day" and "all_leap".
Note that the origins need not be identical, but their parsed values have to be. "2000-01" is parsed the same as "2000-01-01 00:00:00", for instance.
Method parse()
Parsing a vector of date-time character strings into parts.
Method offsets2time()
Decompose a vector of offsets, in units of the calendar, to
their timestamp values. This adds a specified amount of time to the
origin of a CFTime object.
This method may introduce inaccuracies where the calendar unit is "months" or "years", due to the ambiguous definition of these units.