| % File src/library/base/man/Dates.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2018 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{Dates} |
| \alias{Date} |
| \alias{Dates} |
| \alias{print.Date} |
| \alias{summary.Date} |
| \alias{Math.Date} |
| \alias{Summary.Date} |
| \alias{[.Date} |
| \alias{[<-.Date} |
| \alias{length<-.Date} |
| \alias{[[.Date} |
| \alias{as.data.frame.Date} |
| \alias{as.list.Date} |
| \alias{c.Date} |
| \alias{mean.Date} |
| \alias{split.Date} |
| |
| \title{Date Class} |
| \description{ |
| Description of the class \code{"Date"} representing calendar dates. |
| } |
| \usage{ |
| \method{summary}{Date}(object, digits = 12, \dots) |
| |
| \method{print}{Date}(x, max = NULL, \dots) |
| % not sure if we should not rather _drop_ the 'recursive'! |
| %\method{c}{Date}(\dots, recursive = FALSE) |
| } |
| \arguments{ |
| \item{object, x}{a \code{Date} object to be summarized or printed.} |
| \item{digits}{number of significant digits for the computations.} |
| \item{max}{numeric or \code{NULL}, specifying the maximal number of |
| entries to be printed. By default, when \code{NULL}, |
| \code{\link{getOption}("max.print")} used.} |
| \item{\dots}{further arguments to be passed from or to other methods.} |
| %% \item{\dots, recursive}{further arguments to be passed from or to |
| %% other methods; \code{recursive} is not considered in \code{Date} method.} |
| } |
| \details{ |
| Dates are represented as the number of days since 1970-01-01, with |
| negative values for earlier dates. They are always printed |
| following the rules of the current Gregorian calendar, even though |
| that calendar was not in use long ago (it was adopted in 1752 in |
| Great Britain and its colonies). |
| |
| It is intended that the date should be an integer, but this is not |
| enforced in the internal representation. Fractional days will be |
| ignored when printing. It is possible to produce fractional days via |
| the \code{mean} method or by adding or subtracting (see |
| \code{\link{Ops.Date}}). |
| |
| From the many methods, see \code{methods(class = "Date")}, a few are |
| documented separately, see below. |
| } |
| \seealso{ |
| \code{\link{Sys.Date}} for the current date. |
| |
| \code{\link{weekdays}} for convenience extraction functions. |
| |
| Methods with extra arguments and documentation: |
| \describe{ |
| \item{\code{\link{Ops.Date}}}{for operators on \code{"Date"} objects.} |
| |
| \item{\code{\link{format.Date}}}{for conversion to and from character strings.} |
| |
| \item{\code{\link{axis.Date}}}{and \code{\link{hist.Date}} for plotting.} |
| |
| \item{\code{\link{seq.Date}}}{, \code{\link{cut.Date}}, and |
| \code{\link{round.Date}} for utility operations.} |
| } |
| \code{\link{DateTimeClasses}} for date-time classes. |
| } |
| \examples{\donttest{ |
| (today <- Sys.Date()) |
| format(today, "\%d \%b \%Y") # with month as a word |
| (tenweeks <- seq(today, length.out=10, by="1 week")) # next ten weeks |
| weekdays(today) |
| months(tenweeks) |
| }% dont |
| (Dls <- as.Date(.leap.seconds)) |
| |
| ## length(<Date>) <- n now works |
| ls <- Dls; length(ls) <- 12 |
| l2 <- Dls; length(l2) <- 5 + length(Dls) |
| stopifnot(exprs = { |
| ## length(.) <- * is compatible to subsetting/indexing: |
| identical(ls, Dls[seq_along(ls)]) |
| identical(l2, Dls[seq_along(l2)]) |
| ## has filled with NA's |
| is.na(l2[(length(Dls)+1):length(l2)]) |
| }) |
| } |
| \keyword{utilities} |
| \keyword{chron} |