Density and Boxplot Combination (Grouped)

Combines density plots and horizontal boxplots for a numeric variable, optionally grouped by a categorical variable. The density plot shows the distribution shape, while the boxplot summarizes key statistics such as median, spread, and outliers.

Usage

plotDensBox(x, ...)

# Default S3 method
plotDensBox(
  x,
  groups = NULL,
  main = NULL,
  xlab = "",
  ylab = "",
  xlim = NULL,
  heights = c(2, 1.4),
  col = NULL,
  grid = TRUE,
  dens = TRUE,
  box = TRUE,
  stamp = .useTheme,
  ...
)

# S3 method for class 'formula'
plotDensBox(
  formula,
  data,
  subset,
  na.action = na.omit,
  main = NULL,
  xlab = "",
  ...
)

Arguments

x

numeric vector, or a formula of the form x ~ g.

...

further graphical parameters passed to graphics::par() via the internal framework.

groups

optional grouping variable (ignored if a formula is used).

main

main title. NULL (default) draws none, unless the theme sets autoTitle = TRUE (see theme); the title is then derived from the input: the formula, or x resp. x ~ g for the default method. "", NA or FALSE always suppress it and remove its outer margin; any other string is used as given.

xlab

label for the x-axis, drawn below the boxplot. For the formula method, an empty label defaults to the response.

ylab

label for the y-axis of the density panel.

xlim

numeric vector of length 2 specifying the x-axis limits. NULL (default) covers the data and the tails of the densities.

heights

numeric vector of length 2 specifying the relative heights of the density plot (top) and boxplot (bottom).

col

vector of colors, recycled over the groups. If NULL, a palette is generated.

grid

controls drawing of the background grid. Can be:

• TRUE: draw grid with default settings

• FALSE, NULL, NA: suppress grid

• a named list: arguments passed to graphics::grid()

dens

controls density estimation via stats::density(). Can be:

• TRUE: use default density settings

• FALSE, NULL, NA: suppress densities

• a named list: additional arguments passed to stats::density()

box

controls drawing of boxplots via graphics::boxplot(). Can be:

• TRUE: use default boxplot settings

• FALSE, NULL, NA: suppress boxplots

• a named list: additional arguments passed to graphics::boxplot()

stamp

controls the corner stamp. .useTheme (default) resolves to getTheme()$stamp. TRUE/FALSE/NULL, a string, or a named list for stamp().

formula

a formula of the form y ~ group, or y ~ a:b for the cells of several grouping variables. y ~ a + b is not accepted, see bedrock::resolveFormula().

data

an optional data frame containing the variables in the formula.

subset

an optional expression indicating which observations to use, evaluated in data (subset = len > 10), as in boxplot().

na.action

a function specifying how missing values are handled, defaults to na.omit().

Value

Invisibly returns NULL.

Details

The function arranges two plots vertically using layout(): a density plot on top and a horizontal boxplot below. When a grouping variable is provided, densities and boxplots are drawn for each group.

Optional plot components are controlled using bedrock::callIf() semantics:

• TRUE: draw with defaults

• FALSE: suppress component

• named list: customize component arguments

See also

stats::density(), graphics::boxplot(), bedrock::callIf()

Other plot.univariate: plotArea(), plotBar(), plotBox(), plotCatDist(), plotDens(), plotDot(), plotECDF(), plotFreqDist(), plotLines(), plotQQ(), plotViolin()

Examples

set.seed(1)
x <- rnorm(100)
g <- sample(c("A", "B"), 100, TRUE)

plotDensBox(x)

plotDensBox(x, g)


plotDensBox(
  x,
  dens = list(adjust = 2),
  box  = list(notch = TRUE)
)


plotDensBox(
  x,
  box = FALSE
)


plotDensBox(x ~ g)


# subset and the cells of two grouping variables
plotDensBox(len ~ supp:dose, ToothGrowth, subset = dose > 0.5)