R: Bar Plots

barplot {base}

R Documentation

Bar Plots

Description

Creates a bar plot with vertical or horizontal bars.

Usage

barplot(height, width = 1, space = NULL, names.arg = NULL,
        legend.text = NULL, beside = FALSE, horiz = FALSE,
        col = heat.colors(NR), border = par("fg"),
        main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
        xlim = NULL, ylim = NULL,
        axes = TRUE, axisnames = TRUE, inside = TRUE, plot = TRUE, ...)

Arguments

height

either a vector or matrix of values describing the bars which make up the plot. If height is a vector, the plot consists of a sequence of rectangular bars with heights given by the values in the vector. If height is a matrix and beside is FALSE then each bar of the plot corresponds to a column of height, with the values in the column giving the heights of stacked “sub-bars” making up the bar. If height is a matrix and beside is TRUE, then the values in each column are juxtaposed rather than stacked.

width

optional vector of bar widths.

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 height is a matrix and beside is TRUE, 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 c(0,1) if height is a matrix and beside is TRUE, and to 0.2 otherwise.

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 names attribute of height if this is a vector, or the column names if it is a matrix.

legend.text

a vector of text used to construct a legend for the plot. This is only useful when height is a matrix. In that case the legend labels should correspond to the rows of height.

beside

a logical value. If FALSE, the columns of height are portrayed as stacked bars, and if TRUE the columns are portrayed as juxtaposed bars.

horiz

a logical value. If FALSE, the bars are drawn vertically with the first bar to the left. If TRUE, the bars are drawn horizontally with the first at the bottom.

col

a vector of colors for the bars or bar components.

border

the color to be used for the border of the bars.

main, sub

overall and sub title for the plot.

xlab

a label for the x axis.

ylab

a label for the y axis.

xlim

limits for the x axis.

ylim

limits for the y axis.

axes

logical. If TRUE, a vertical (or horizontal, if horiz is true) axis is drawn.

axisnames

logical. If TRUE, and if there are names.arg (see above), the other axis is drawn (with lty=0) and labeled.

plot

logical. If FALSE, nothing is plotted.

...

further graphical parameters (par) are passed to plot.window() and title().

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 beside = TRUE), say mp, giving the coordinates of all the bar midpoints drawn, useful for adding to the graph.

If beside is true, use apply(mp, 2, mean) for the midpoints of each group of bars, see example.

Examples

tN <- table(Ni <- rpois(100, lambda=5))
r <- barplot(tN, col='gray')
#- 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)")

data(VADeaths, package = "base")
barplot(VADeaths, plot = FALSE)
barplot(VADeaths, plot = FALSE, beside = TRUE)

mp <- barplot(VADeaths) # default
tot <- apply(VADeaths, 2, sum)
text(mp, tot + 3, format(tot), xpd = NA, 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)
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 = apply(mp, 2, mean), line = -2,
      text = paste("Mean", formatC(apply(hh, 2, mean))), col = "red")

[Package base version 1.1 ]