The R Project SVN R

\name{axis}
\title{Add an Axis to a Plot}
\usage{
axis(side, at, labels=TRUE, \dots)
}
\alias{axis}
\arguments{
\item{side}{an integer specifying which side of the plot
    the axis is to be drawn on.}
\item{at}{the points at which tick-marks are to be drawn.}
\item{labels}{this can either be a logical value specifying
    whether (numerical) annotations are to be made at
    the tickmarks, or a vector of character strings to be placed
    at the tickpoints.}
\item{\dots}{graphical parameters may also be passed as
    arguments to this function.}
}
\value{
This function is invoked for its side effect,
which is to add an axis to an already existing plot.
The axis is placed as follows:
1=below, 2=left, 3=above and 4=right.
}
\examples{
plot(1:4, rnorm(4), axes=FALSE)
axis(1, 1:4, LETTERS[1:4])
axis(2)
box() #- to make it look "as usual"

plot(1:7, rnorm(7), type = 's', xaxt='n', col = 'red')
axis(1, 1:7, LETTERS[1:7], col.axis = 'blue')
\testonly{ # test sorting of labels
Y <- c(10.50, 4.0, 13.75, 7.25)
plot(1:4, Y, xlim=c(0,5), ylim=c(0,15))
axis(side=4, at=Y, labels=LETTERS[1:4])
}
}
\keyword{aplot}