gap.boxplot: Display a boxplot with a gap (missing range)

Description

Displays a boxplot with a missing range.

Usage

gap.boxplot(x,...,gap=list(top=c(NA,NA),bottom=c(NA,NA)),
 range=1.5,width=NULL,varwidth=FALSE,notch=FALSE,outline=TRUE,
 names,xlim=NA,ylim=NA,plot=TRUE,border=par("fg"),col=NULL,log="",
 axis.labels=NULL,axes=TRUE,pars=list(boxwex=0.8,staplewex=0.5,outwex=0.5),
 horizontal=FALSE,add=FALSE,at=NULL,main=NULL)

Arguments

numeric vector or a list of vectors

...

arguments passed to boxplot.

gap

the range(s) to be omitted - a list with two components, top and bottom each specifying a range to omit. The default range of c(NA,NA) means no omitted range

range

how far to extend the whiskers, (see boxplot)

width

the relative widths of the boxes

varwidth

if TRUE, box widths are proportional to the square roots of the number of observations

notch

whether to display the confidence intervals for the median as notches

outline

whether to display outliers

names

optional names to display beneath each boxplot

xlim,ylim

Optional x and y axis limits for the plot.

boxwex

scale factor for box widths

staplewex

staple width proportional to box width

outwex

outlier line width

plot

dummy argument for consistency with boxplot - always plots

border

optional color(s) for the box lines

col

optional color(s) to fill the boxes

log

whether to use a log scale - currently does nothing

axis.labels

Optional axis labels.

axes

Whether to display axes.

pars

optional parameters for consistency with boxplot

horizontal

whether to plot horizontal boxplots - currently does nothing

add

whether to add the boxplot(s) to a current plot - currently does nothing.

optional horizontal locations for the boxplots.

main

a title for the plot.

Value

A list with the same structure as returned by boxplot, except that the values of elements beyond the gap(s) have their true positions on the plot rather than the original values. For example, in the second example, the value returned for the upper staple of the right boxplot is 14 rather than 20, due to the 6 unit gap.

Details

Displays boxplot(s) omitting range(s) of values on the top and/or bottom of the plot. Typically used when there are outliers far from the boxes. See boxplot for more detailed descriptions of the arguments. If the gaps specified include any of the values in the stats matrix returned from boxplot, the function will exit with an error message. This prevents generation of NAs in indexing operations, which would fail anyway. A gap can include part of a box, but it is unlikely that this would be intended by the user.

See axis.break for a brief discussion of plotting on discontinuous coordinates.

Examples

Run this code

# NOT RUN {
 twovec<-list(vec1=c(rnorm(30),-6),vec2=c(sample(1:10,40,TRUE),20))
 gap.boxplot(twovec,gap=list(top=c(12,18),bottom=c(-5,-3)),
 main="Show outliers separately")
 if(dev.interactive()) par(ask=TRUE)
 gap.boxplot(twovec,gap=list(top=c(12,18),bottom=c(-5,-3)),range=0,
 main="Include outliers in whiskers")
 par(ask=FALSE)
# }