CFtime 1.7.2

Maintenance release

• Time units can use SI decimal multiples or sub-multiples, such as "µs" or "kiloyear".
• Setting bad boundary values generates a warning instead of an error.
• CFCalendar and subclasses use active fields for all properties.
• CRAN landing page links to github.io documentation.

CFtime 1.7.1

Maintenance release

• Added length field to class CFTime.
• Added format.CFTime() S3 method.
• Added "[.CFTime" S3 method.
• Documentation has been moved from vignettes to a website on github.io.

CFtime 1.7.0

• CFtime is now hosted on Github through the R-CF organization: all things related to the CF Metadata Conventions in R.
• New sequence-like method to create CFTime instances.
• New methods CFTime$copy() and CFTime$subset() to create copies of the entire CFTime instance or a subset thereof, including boundary values if they are set.
• Fixed error on year 0 timestamps.

CFtime 1.6.1

• Deprecated "gregorian" calendar automatically converted to the equivalent "standard".
• CFCalendar$add_day() method added to add a day to a data.frame of date parts, using calendar logic.
• API change: Bounds are now always fully specified so logical arguments should no longer be used, except in setting regular, consecutive bounds (bounds <- TRUE). If bounds have not been set, a NULL value is returned. This is to ensure that factorizing to "approximate" time units (such as a month) will give correct results for the bounds. (Old API deprecated by November 2025, removed early 2026.)

CFtime 1.6.0

• New class CFClimatology to manage climatological statistics. Method
  CFTime$factor() with an era argument will now have a CFClimatology
  instance attached to the attribute "CFTime" of its return value.
• New class CFCalendarNone for a calendar with no annual cycle. Such a
  calendar represents a single instant in time, which may be useful for
  experiments on a fixed moment during the year.
• str() for CFTime and CFClimatology gives compact information.
• Fixed new CFTime instance for factor with a "day" or "dekad" period where
  the last factor level is not at the end of the year.
• CFTime$new() with a single character string offset will generate only the
  single corresponding offset.
• Test coverage near-complete.
• Fixed inconsistent documentation for functions.
• Minor code fixes.

CFtime 1.5.1

• CFTime$slice() can now work with a single or multiple timestamp values.
• Test coverage increased.
• Documentation updated, all runnable example code uses ncdfCF package.
• Minor code fixes.

CFtime 1.5.0

• Code is updated to align with the CF 1.12 release. Specifically, calendars
  utc and tai are added.
• standard calendar now uses mixed Gregorian/Julian calendar as defined in the
  CF Metadata Conventions. proleptic_gregorian is now a separate calendar with
  its own code base.
• Negative offsets from a calendar origin are allowed.
• Code is refactored to R6. R6 class CFTime replaces S4 class CFtime (note the
  difference in case). S4 class CFdatum has been replaced by hierarchy of
  R6 CFCalendar classes, with various non-exported functions converted into
  methods of CFCalendar. The code is now much cleaner and easier to extend, such
  as with the two new calendars utc and tai.
• ISO8601 timestamps can use a comma "," as decimal mark to separate a
  fractional part from a time element, in addition to the dot ".".
• Do not drop degenerate dimension on bounds when only 1 offset is included in
  subsetting.

CFtime 1.4.1

• Method slab() has an additional argument rightmost.closed to indicate if
  the upper extreme value should be included in the result.
• Fixed bounds information on CFtime instances returned from methods indexOf()
  and slab().
• Several minor code improvements.

CFtime 1.4.0

• Bounds that define intervals around offsets can be associated with a CFtime
  instance and retrieved as raw offset values or as formatted timestamps.
• Methods that subset a CF time series (e.g. CFfactor(), cut(), slab())
  now have an attribute "CFtime" (among possible others) that describes the "time"
  dimension of the analysis result applying the subset. In other words, if CFtime
  instance 'Acf' describes the temporal dimension of data set 'A' and a factor 'Af'
  is generated from 'Acf', then Bcf <- attr(Af, "CFtime") describes the temporal
  dimension of the result of, say, B <- apply(A, 1:2, tapply, Af, FUN).
• New indexOf() method added that returns the indices of supplied timestamps
  in a CFtime instance, optionally with a fractional part. This can be used to
  extract specific time steps, or to interpolate between time steps using the
  fractional part, from the time dimension of the data set associated with the
  CFtime instance. A vector of indices (e.g. referring to slices of the data set)
  can also be supplied, in which case valid indices are returned, with the new
  CFtime instance.
• New cut() method added to generate a factor, similar to cut.POSIXt() but with
  some differences in the arguments.
• CFfactor() now supports a period "quarter", for calendar quarters.
• format() method added that generates a character vector of timestamps for the
  offsets in a CFtime instance. The format is specified using the flags used in
  strptime(), with some limitations. In particular, locale-specific formatting is
  limited to month names and no weekday information can be generated. The range()
  method has a new "format" parameter to support the same functionality and timestamps
  can also be generated for the extremes of the bounds, if set.
• as.character() and length() methods added that return a vector of timestamps
  or the number of offsets in a CFtime instance, respectively.
• Several functions have been renamed (most notably CFtimestamp() to
  as.timestamp(), CFcomplete() to is_complete(), CFrange() to the standard
  generic method range(), and CFsubset() to slab()) to be more consistent
  with the R universe. The original functions are now flagged as being deprecated.
  Some datum functions (deep down where regular mortals do not dwell) have been
  deleted.
• Time zone designator "UTC" accepted when parsing timestamps to offsets.
• Minor code fixes, see GitHub commits.
• Documentation updated, with description of new functions.

CFtime 1.3.0

Changes since release 1.2.0:

• Two CFtime instances can be added if they have compatible calendars and units.
  The earlier origin is preserved in the result and offsets from the later instance
  are incremented by the appropriate amount. As before, in the result offsets are
  in the order of the specified CFtime instances.
• A new function CFsubset() can be used to retrieve a logical vector that indicates
  which time steps in a CFtime instance fall between two timestamps. This is useful
  to slice data during reading from file or analysis.
• Time zone information is managed at the level of the datum. If a vector of character
  timestamps is parsed and found to have different time zones, a warning is generated.
• Much reduced memory footprint.
• Minor code fixes, see GitHub commits.
• Codecov.io test coverage monitoring added.
• Documentation updated, with description of new functions.