Dates
Date Class
Description of the class "Date" representing calendar dates.
Usage
# S3 method for Date
summary(object, digits = 12, …)# S3 method for Date
print(x, max = NULL, …)
Arguments
- object, x
a
Dateobject to be summarized or printed.- digits
number of significant digits for the computations.
- max
numeric or
NULL, specifying the maximal number of entries to be printed. By default, whenNULL,getOption("max.print")used.- …
further arguments to be passed from or to other methods.
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 mean method or by adding or subtracting (see
Ops.Date).
From the many methods, see methods(class = "Date"), a few are
documented separately, see below.
See Also
Sys.Date for the current date.
weekdays for convenience extraction functions.
Methods with extra arguments and documentation:
Ops.Datefor operators on
"Date"objects.format.Datefor conversion to and from character strings.
axis.Dateand
hist.Datefor plotting.seq.Date,
cut.Date, andround.Datefor utility operations.
DateTimeClasses for date-time classes.
Examples
library(base)
# NOT RUN {
(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)
# }
# NOT RUN {
<!-- % dont -->
# }
# NOT RUN {
(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)])
})
# }