| axis.POSIXct {base} | R Documentation |
Functions to plot objects of classes "POSIXlt" and
"POSIXct" representing calendar dates and times.
axis.POSIXct(side, x, at, format, ...) ## S3 method for class 'POSIXct': plot(x, y, xlab = "", ...) ## S3 method for class 'POSIXlt': plot(x, y, xlab = "", ...)
x, at |
A date-time object. |
y |
numeric values to be plotted against x. |
xlab |
a character string giving the label for the x axis. |
side |
See axis. |
format |
See strptime. |
... |
Further arguments to be passed from or to other methods,
typically graphical parameters or arguments of
plot.default. |
The functions plot against an x-axis of date-times.
axis.POSIXct works quite hard to choose suitable time units
(years, months, days, hours, minutes or seconds) and a sensible
output format, but this can be overridden by supplying a format
specification.
If at is supplied for axis.POSIXct it specifies the
locations of the ticks and labels: if x is specified a
suitable grid of labels is chosen.
DateTimeClasses for details of the classes.
res <- try(data(beav1, package = "MASS"))
if(!inherits(res, "try-error")) {
attach(beav1)
time <- strptime(paste(1990, day, time %/% 100, time %% 100),
"%Y %j %H %M")
plot(time, temp, type="l") # axis at 4-hour intervals.
# now label every hour on the time axis
plot(time, temp, type="l", xaxt="n")
r <- as.POSIXct(round(range(time), "hours"))
axis.POSIXct(1, at=seq(r[1], r[2], by="hour"), format="%H")
rm(time)
detach(beav1)
}
plot(.leap.seconds, 1:22, type="n", yaxt="n",
xlab="leap seconds", ylab="", bty="n")
rug(.leap.seconds)