| axis.POSIXct {graphics} | R Documentation |
Functions to plot objects of classes "POSIXlt",
"POSIXct" and "Date" representing calendar dates and times.
axis.POSIXct(side, x, at, format, labels = TRUE, ...) axis.Date(side, x, at, format, labels = TRUE, ...)
x, at |
A date-time or date object. |
side |
See |
format |
See |
labels |
Either a logical value specifying whether annotations are to be made at the tickmarks, or a vector of character strings to be placed at the tickpoints. |
... |
Further arguments to be passed from or to other methods, typically graphical parameters. |
axis.POSIXct and axis.Date work 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 it specifies the locations of the ticks
and labels whereas if x is specified a suitable grid of labels
is chosen. Printing of tick labels can be suppressed by using
labels = FALSE.
The date-times for a "POSIXct" input are interpreted in the
time zone give by the "tzone" attribute if there is one,
otherwise the current time zone.
The way the date-times are rendered (especially month names) is
controlled by the locale setting of category "LC_TIME" (see
Sys.setlocale).
The locations on the axis scale at which tick marks were drawn.
DateTimeClasses, Dates for details of the classes.
Axis.
with(beaver1, {
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")
})
plot(.leap.seconds, seq_along(.leap.seconds), type = "n", yaxt = "n",
xlab = "leap seconds", ylab = "", bty = "n")
rug(.leap.seconds)
## or as dates
lps <- as.Date(.leap.seconds)
plot(lps, seq_along(.leap.seconds),
type = "n", yaxt = "n", xlab = "leap seconds",
ylab = "", bty = "n")
rug(lps)
## 100 random dates in a 10-week period
random.dates <- as.Date("2001/1/1") + 70*sort(stats::runif(100))
plot(random.dates, 1:100)
# or for a better axis labelling
plot(random.dates, 1:100, xaxt = "n")
axis.Date(1, at = seq(as.Date("2001/1/1"), max(random.dates)+6, "weeks"))
axis.Date(1, at = seq(as.Date("2001/1/1"), max(random.dates)+6, "days"),
labels = FALSE, tcl = -0.2)