The “densityplot” Function in R

• Package: lattice

• Purpose: Create kernel density plots.

• General class: Visualization

• Required argument(s):

• x: A numeric vector, formula, or an object coercible to such.

• Notable optional arguments:

• data: A data frame containing variables in the formula.

• groups: An optional grouping variable.

• plot.points: Logical; whether to plot the original points.

• auto.key: Logical or list; whether to draw a key.

• Example:

• # Load the required library
  library(lattice)
  
  # Create a sample dataset
  data <- data.frame(
  value = c(rnorm(100, mean = 0), rnorm(100, mean = 3)),
  group = factor(rep(1:2, each = 100))
  )
  
  # Create a density plot
  densityplot(~ value, data = data, groups = group,
  plot.points = TRUE, auto.key = TRUE)

• In this example, the densityplot function from the lattice package is used to create a kernel density plot. The dataset data contains two groups with different distributions. The densityplot function creates a density plot for the value variable, with different colors for each group. The plot.points argument is set to TRUE to include the original data points on the plot, and auto.key is set to TRUE to automatically generate a legend.