Barplot: Bar Plots

Description

Create bar plots for one or two factors scaled by frequency or precentages. In the case of two factors, the bars can be divided (stacked) or plotted in parallel (side-by-side). This function is a front end to barplot in the graphics package.

Usage

Barplot(x, by, scale = c("frequency", "percent"), conditional=TRUE,
  style = c("divided", "parallel"), 
  col=if (missing(by)) "gray" else rainbow_hcl(length(levels(by))),
  xlab = deparse(substitute(x)), legend.title = deparse(substitute(by)), 
  ylab = scale, main=NULL, legend.pos = "above", label.bars=FALSE, ...)

Value

Invisibly returns the horizontal coordinates of the centers of the bars.

Arguments

x: a factor (or character or logical variable).
by: optionally, a second factor (or character or logical variable).
scale: either "frequency" (the default) or "percent".
conditional: if TRUE then percentages are computed separately for each value of x (i.e., conditional percentages of by within levels of x); if FALSE then total percentages are graphed; ignored if scale="frequency".
style: for two-factor plots, either "divided" (the default) or "parallel".
col: if by is missing, the color for the bars, defaulting to "gray"; otherwise colors for the levels of the by factor in two-factor plots, defaulting to colors provided by rainbow_hcl in the colorspace package.
xlab: an optional character string providing a label for the horizontal axis.
legend.title: an optional character string providing a title for the legend.
ylab: an optional character string providing a label for the vertical axis.
main: an optional main title for the plot.
legend.pos: position of the legend, in a form acceptable to the legend function; the default, "above", puts the legend above the plot.
label.bars: if TRUE (the default is FALSE) show values of frequencies or percents in the bars.
...: arguments to be passed to the barplot function.

Author

John Fox jfox@mcmaster.ca

Examples

Run this code

with(Mroz, {
  Barplot(wc)
  Barplot(wc, col="lightblue", label.bars=TRUE)
  Barplot(wc, by=hc)
  Barplot(wc, by=hc, scale="percent", label.bars=TRUE)
  Barplot(wc, by=hc, style="parallel", 
    scale="percent", legend.pos="center")
})