barplot                 package: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, density = NULL, angle = 45,
             col = heat.colors(NR), border = par("fg"),
             main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
             xlim = NULL, ylim = NULL,
             axes = TRUE, axisnames = TRUE,
             cex.axis = par("cex.axis"), cex.names = par("cex.axis"),
             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. Re-cycled to length the number
          of bars drawn.  Specifying a single value will no visible
          effect unless `xlim' is specified.

   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,
          or a logical indicating whether a legend should be included. 
          This is only useful when `height' is a matrix. In that case
          given legend labels should correspond to the rows of
          `height'; if `legend.text' is true, the row names of `height'
          will be used as labels if they are non-null.

  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.

 density: a vector giving the the density of shading lines, in lines
          per inch, for the bars or bar components. The default value
          of `NULL' means that no shading lines are drawn. Non-positive
          values of `density' also inhibit the drawing of shading
          lines.

   angle: the slope of shading lines, given as an angle in degrees
          (counter-clockwise), for the bars or bar components.

     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.

cex.axis: expansion factor for numeric axis labels.

cex.names: expansion factor for names.

  inside: logical.  If `TRUE', the lines which  divide adjacent bars
          will be drawn.

    plot: logical.  If `FALSE', nothing is plotted.

     ...: further graphical parameters (`par') are passed to
          `plot.window()', `title()' and `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 `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.

See Also:

     `plot(..., type="h")', `dotchart', `hist'.

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 = 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 = apply(mp, 2, mean), line = -2,
           text = paste("Mean", formatC(apply(hh, 2, mean))), 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))

