#activate the package
library(ggplot2)

#load the dataframe
ID <- 1:400
values <- c(rnorm(200, mean=50, sd=22), rnorm(200, mean=20, sd=10))
class <- c(rep("first", 200), rep("second",200))
my.dataframe <- data.frame(ID, values, class)

#violin plot 
ggplot(my.dataframe, aes(class, values)) + 
  geom_violin()

#untrimmed violin plot
ggplot(my.dataframe, aes(class, values)) + 
  geom_violin(trim=FALSE)


#untrimmed violin plot with 2 colors and the legend
ggplot(my.dataframe, aes(class, values, fill=class)) + 
  geom_violin(trim=FALSE)


#untrimmed violin plot with 2 colors, boxplots and the legend
ggplot(my.dataframe, aes(class, values, fill=class)) + 
  geom_violin(trim=FALSE) +
  geom_boxplot(width=0.1, fill="yellow")