pretty.Date {grDevices}

R Documentation

Pretty Breakpoints for Date-Time Classes

Description

Compute a sequence of about n+1 equally spaced ‘nice’ values which cover the range of the values in x, possibly of length one, when min.n = 0 and there is only one unique x.

Usage

## S3 method for class 'Date'
pretty(x, n = 5, min.n = n %/% 2, sep = " ", ...)
## S3 method for class 'POSIXt'
pretty(x, n = 5, min.n = n %/% 2, sep = " ", ...)

Arguments

x	an object of class "Date" or "POSIXt" (i.e., "POSIXct" or "POSIXlt").
n	integer giving the desired number of intervals.
min.n	nonnegative integer giving the minimal number of intervals.
sep	character string, serving as a separator for certain formats (e.g., between month and year).
...	further arguments for compatibility with the generic, ignored.

Value

A vector (of the suitable class) of locations, with attribute "labels" giving corresponding formatted character labels and attribute "format" giving the format specification that was used.

See Also

pretty for the default method.

Examples

## time-dependent ==> ignore diffs:
## IGNORE_RDIFF_BEGIN
pretty(Sys.Date())
pretty(Sys.time(), n = 10)
## IGNORE_RDIFF_END

pretty(as.Date("2000-03-01")) # R 1.0.0 came in a leap year

## time ranges in diverse scales:% also in ../../../../tests/reg-tests-1c.R
require(stats)
steps <- setNames(,
    c("10 secs", "1 min", "5 mins", "30 mins", "6 hours", "12 hours",
      "1 DSTday", "2 weeks", "1 month", "6 months", "1 year",
      "10 years", "50 years", "1000 years"))
x <- as.POSIXct("2002-02-02 02:02")
lapply(steps,
       function(s) {
           at <- pretty(seq(x, by = s, length.out = 2), n = 5)
           attr(at, "labels")
       })

---