R: Box Plots from Summaries

bxp {base}

R Documentation

Box Plots from Summaries

Description

bxp draws box plots based on the given summaries in z. It is usually called from within boxplot, but can be invoked directly.

Usage

bxp(z, notch = FALSE, width = NULL, varwidth = FALSE, outline = TRUE,
    notch.frac = 0.5, boxwex = 0.8, border = par("fg"), col = NULL,
    log = "", pars = NULL, frame.plot = axes, horizontal = FALSE,
    add = FALSE, at = NULL, show.names=NULL, ...)

Arguments

`z`	a list containing data summaries to be used in constructing the plots. These are usually the result of a call to `boxplot`, but can be generated in any fashion.
`notch`	if `notch` is `TRUE`, a notch is drawn in each side of the boxes. If the notches of two plots do not overlap then the medians are significantly different at the 5 percent level.
`width`	a vector giving the relative widths of the boxes making up the plot.
`varwidth`	if `varwidth` is `TRUE`, the boxes are drawn with widths proportional to the square-roots of the number of observations in the groups.
`outline`	if `outline` is not true, the boxplot lines are not drawn.
`boxwex`	a scale factor to be applied to all boxes. When there are only a few groups, the appearance of the plot can be improved by making the boxes narrower.
`notch.frac`	numeric in (0,1). When `notch=TRUE`, the fraction of the box width that the notches should use.
`border`	character, the color of the box borders. Is recycled for multiple boxes.
`col`	character; the color within the box. Is recycled for multiple boxes
`log`	character, indicating if any axis should be drawn in logarithmic scale, as in `plot.default`.
`frame.plot`	logical, indicating if a “frame” (`box`) should be drawn; defaults to `TRUE`, unless `axes = FALSE` is specified.
`horizontal`	logical indicating if the boxplots should be horizontal; default `FALSE` means vertical boxes.
`add`	logical, if true add boxplot to current plot.
`at`	numeric vector giving the locations where the boxplots should be drawn, particularly when `add = TRUE`; defaults to `1:n` where `n` is the number of boxes.
`show.names`	Set to `TRUE` or `FALSE` to override the defaults on whether an x-axis label is printed for each group.
`pars`, `...`	graphical parameters can be passed as arguments to this function, either as a list (`pars`) or normally(`...`). Currently, `pch`, `cex`, and `bg` are passed to `points`, `ylim` and `axes` to the main plot (`plot.default`), `xaxt`, `yaxt`, `las` to `axis` and the others to `title`.

Value

An invisible vector, actually identical to the at argument, with the coordinates ("x" if horizontal is false, "y" otherwise) of box centers, useful for adding to the plot.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth \& Brooks/Cole.

Examples

set.seed(753)
str(bx.p <- boxplot(split(rt(100, 4), gl(5,20))))
op <- par(mfrow= c(2,2))
bxp(bx.p, xaxt = "n")
bxp(bx.p, notch = TRUE, axes = FALSE, pch = 4)
bxp(bx.p, notch = TRUE, col= "lightblue", frame= FALSE, outl= FALSE,
    main = "bxp(*, frame= FALSE, outl= FALSE)")
bxp(bx.p, notch = TRUE, col= "lightblue", border="red", ylim = c(-4,4),
    pch = 22, bg = "green", log = "x", main = "... log='x', ylim=*")
par(op)
op <- par(mfrow= c(1,2))
data(PlantGrowth)
## single group -- no label
boxplot(weight~group,data=PlantGrowth,subset=group=="ctrl")
bx<-boxplot(weight~group,data=PlantGrowth,subset=group=="ctrl",plot=FALSE)
## with label
bxp(bx,show.names=TRUE)
par(op)

[Package base version 1.7.1 ]