Basic Multiple Density Plot
To make multiple density plots with coloring by variable in R with ggplot2, we firstly make a data frame with values and category. Then we draw the ggplot2 density plot using the geom_desnity() function. To color them according to the variable we add the fill property as a category in the ggplot() function.
Syntax:
ggplot(dataFrame, aes( x, color, fill)) + geom_density()
Example:
We get multiple density plots in the ggplot of two colors corresponding to two-level/values for the second categorical variable. If our categorical variable has n levels, then ggplot2 would make multiple density plots with n densities/color.
R
# load library library(tidyverse) set.seed(1234) # create the dataframe df <- data.frame( category=factor(rep(c("category1", "category2","category3"), each=1000)), value=round(c(rnorm(1000, mean=65, sd=5), rnorm(1000, mean=85, sd=5), rnorm(1000, mean=105, sd=5)))) # Basic density plot with custom color # color property to determine the color of plot # fill property to determine the color beneath plot ggplot(df, aes(x=value, color=category, fill=category)) + geom_density(alpha=0.3) |
Output:
How to Add Vertical Lines By a Variable in Multiple Density Plots with ggplot2 in R
In this article, we will discuss how to add vertical lines by a variable in multiple density plots with ggplot2 package in the R Programming language.
To do so first we will create multiple density plots colored by group and then add the line as a separate element.