The R Project SVN R

% File src/library/graphics/man/barplot.Rd

% Part of the R package, http://www.R-project.org

% Copyright 1995-2007 R Core Team

% Distributed under GPL 2 or later

\name{barplot}

\alias{barplot}

\alias{barplot.default}

\title{Bar Plots}

\description{

  Creates a bar plot with vertical or horizontal bars.

}

\usage{

barplot(height, \dots)

\method{barplot}{default}(height, width = 1, space = NULL,

        names.arg = NULL, legend.text = NULL, beside = FALSE,

        horiz = FALSE, density = NULL, angle = 45,

        col = NULL, border = par("fg"),

        main = NULL, sub = NULL, xlab = NULL, ylab = NULL,

        xlim = NULL, ylim = NULL, xpd = TRUE, log = "",

        axes = TRUE, axisnames = TRUE,

        cex.axis = par("cex.axis"), cex.names = par("cex.axis"),

        inside = TRUE, plot = TRUE, axis.lty = 0, offset = 0,

        add = FALSE, args.legend = NULL, \dots)

}

\arguments{

  \item{height}{either a vector or matrix of values describing the

    bars which make up the plot.  If \code{height} is a vector, the

    plot consists of a sequence of rectangular bars with heights

    given by the values in the vector.  If \code{height} is a matrix

    and \code{beside} is \code{FALSE} then each bar of the plot

    corresponds to a column of \code{height}, with the values in the

    column giving the heights of stacked sub-bars making up the

    bar.  If \code{height} is a matrix and \code{beside} is

    \code{TRUE}, then the values in each column are juxtaposed

    rather than stacked.}

  \item{width}{optional vector of bar widths. Re-cycled to length the

    number of bars drawn.  Specifying a single value will have no

    visible effect unless \code{xlim} is specified.}

  \item{space}{the amount of space (as a fraction of the average bar

    width) left before each bar.  May be given as a single number or

    one number per bar.  If \code{height} is a matrix and

    \code{beside} is \code{TRUE}, \code{space} may be specified by

    two numbers, where the first is the space between bars in the

    same group, and the second the space between the groups.  If not

    given explicitly, it defaults to \code{c(0,1)} if \code{height}

    is a matrix and \code{beside} is \code{TRUE}, and to 0.2

    otherwise.}

  \item{names.arg}{a vector of names to be plotted below each bar or

    group of bars.  If this argument is omitted, then the names are

    taken from the \code{names} attribute of \code{height} if this

    is a vector, or the column names if it is a matrix.}

  \item{legend.text}{a vector of text used to construct a legend for

    the plot, or a logical indicating whether a legend should be

    included.  This is only useful when \code{height} is a matrix.

    In that case given legend labels should correspond to the rows of

    \code{height}; if \code{legend.text} is true, the row names of

    \code{height} will be used as labels if they are non-null.}

  \item{beside}{a logical value.  If \code{FALSE}, the columns of

    \code{height} are portrayed as stacked bars, and if \code{TRUE}

    the columns are portrayed as juxtaposed bars.}

  \item{horiz}{a logical value.  If \code{FALSE}, the bars are drawn

    vertically with the first bar to the left.  If \code{TRUE}, the

    bars are drawn horizontally with the first at the bottom.}

  \item{density}{a vector giving the density of shading lines, in

    lines per inch, for the bars or bar components.

    The default value of \code{NULL} means that no shading lines

    are drawn. Non-positive values of \code{density} also inhibit the

    drawing of shading lines.}

  \item{angle}{the slope of shading lines, given as an angle in

    degrees (counter-clockwise), for the bars or bar components.}

  \item{col}{a vector of colors for the bars or bar components.

    By default, grey is used if \code{height} is a vector, and a

    gamma-corrected grey palette if \code{height} is a matrix.}

  \item{border}{the color to be used for the border of the bars.

    Use \code{border = NA} to omit borders.  If there are shading

    lines, \code{border = TRUE} means use the same colour for

    the border as for the shading lines.}

  \item{main,sub}{overall and sub title for the plot.}

  \item{xlab}{a label for the x axis.}

  \item{ylab}{a label for the y axis.}

  \item{xlim}{limits for the x axis.}

  \item{ylim}{limits for the y axis.}

  \item{xpd}{logical. Should bars be allowed to go outside region?}

  \item{log}{string specifying if axis scales should be logarithmic; see

    \code{\link{plot.default}}.}

  \item{axes}{logical.  If \code{TRUE}, a vertical (or horizontal, if

    \code{horiz} is true) axis is drawn.}

  \item{axisnames}{logical.  If \code{TRUE}, and if there are

    \code{names.arg} (see above), the

    other axis is drawn (with \code{lty = 0}) and labeled.}

  \item{cex.axis}{expansion factor for numeric axis labels.}

  \item{cex.names}{expansion factor for axis names (bar labels).}

  \item{inside}{logical.  If \code{TRUE}, the lines which divide

    adjacent (non-stacked!) bars will be drawn.  Only applies when

    \code{space = 0} (which it partly is when \code{beside = TRUE}).}

%MM: we still have "NotYetUsed" -- the above describes S-plus 6.1 (not

% precisely documented!) behavior!

  \item{plot}{logical.  If \code{FALSE}, nothing is plotted.}

  \item{axis.lty}{the graphics parameter \code{lty} applied to the axis

    and tick marks of the categorical (default horizontal) axis.  Note

    that by default the axis is suppressed.}

  \item{offset}{a vector indicating how much the bars should be shifted

    relative to the x axis.}

  \item{add}{logical specifying if bars should be added to an already

    existing plot; defaults to \code{FALSE}.}

  \item{args.legend}{list of additional arguments to pass to

    \code{\link{legend}()}; names of the list are used as argument

    names.  Only used if \code{legend.text} is supplied.}

  \item{\dots}{arguments to be passed to/from other methods.  For the

    default method these can include further arguments (such as

    \code{axes}, \code{asp} and \code{main}) and

    \link{graphical parameters} (see \code{\link{par}}) which are passed to

    \code{\link{plot.window}()}, \code{\link{title}()} and

    \code{\link{axis}}.}

}

\details{

  This is a generic function, it currently only has a default method.

  A formula interface may be added eventually.

}

\value{

  A numeric vector (or matrix, when \code{beside = TRUE}), say

  \code{mp}, giving the coordinates of \emph{all} the bar midpoints

  drawn, useful for adding to the graph.

  If \code{beside} is true, use \code{colMeans(mp)} for the

  midpoints of each \emph{group} of bars, see example.

}

\references{

  Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)

  \emph{The New S Language}.

  Wadsworth & Brooks/Cole.

  Murrell, P. (2005) \emph{R Graphics}. Chapman & Hall/CRC Press.

}

\seealso{

  \code{\link{plot}(\dots, type = "h")}, \code{\link{dotchart}},

  \code{\link{hist}}.

}

\examples{

require(grDevices) # for colours

tN <- table(Ni <- stats::rpois(100, lambda = 5))

r <- barplot(tN, col = rainbow(20))

#- type = "h" plotting *is* 'bar'plot

lines(r, tN, type = "h", col = "red", lwd = 2)

barplot(tN, space = 1.5, axisnames = FALSE,

        sub = "barplot(..., space= 1.5, axisnames = FALSE)")

barplot(VADeaths, plot = FALSE)

barplot(VADeaths, plot = FALSE, beside = TRUE)

mp <- barplot(VADeaths) # default

tot <- colMeans(VADeaths)

text(mp, tot + 3, format(tot), xpd = TRUE, col = "blue")

barplot(VADeaths, beside = TRUE,

        col = c("lightblue", "mistyrose", "lightcyan",

                "lavender", "cornsilk"),

        legend = rownames(VADeaths), ylim = c(0, 100))

title(main = "Death Rates in Virginia", font.main = 4)

hh <- t(VADeaths)[, 5:1]

mybarcol <- "gray20"

mp <- barplot(hh, beside = TRUE,

        col = c("lightblue", "mistyrose",

                "lightcyan", "lavender"),

        legend = colnames(VADeaths), ylim = c(0,100),

        main = "Death Rates in Virginia", font.main = 4,

        sub = "Faked upper 2*sigma error bars", col.sub = mybarcol,

        cex.names = 1.5)

segments(mp, hh, mp, hh + 2*sqrt(1000*hh/100), col = mybarcol, lwd = 1.5)

stopifnot(dim(mp) == dim(hh))  # corresponding matrices

mtext(side = 1, at = colMeans(mp), line = -2,

      text = paste("Mean", formatC(colMeans(hh))), col = "red")

# Bar shading example

barplot(VADeaths, angle = 15+10*1:5, density = 20, col = "black",

        legend = rownames(VADeaths))

title(main = list("Death Rates in Virginia", font = 4))

# border :

barplot(VADeaths, border = "dark blue") % lwd = 2 << not passed

%notyet barplot(VADeaths, inside = FALSE, main = "barplot(*, inside = FALSE)")

# log scales (not much sense here):

barplot(tN, col = heat.colors(12), log = "y")

barplot(tN, col = gray.colors(20), log = "xy")

# args.legend

barplot(height = cbind(x = c(465, 91) / 465 * 100,

                       y = c(840, 200) / 840 * 100,

                       z = c(37, 17) / 37 * 100),

        beside = FALSE,

        width = c(465, 840, 37),

        col = c(1, 2),

        legend.text = c("A", "B"),

        args.legend = list(x = "topleft"))

}

\keyword{hplot}