r中数据点的绘图数量

Question

I am using the following in R to generate a Boxplot out of a given set of data:

ggplot(data = daten, aes(x=Bodentyp, y=Fracht)) + geom_boxplot(aes(fill=Bewirtschaftungsform))

Now I want to display the number of data points going into each category of the column "Bodentyp". How do I achieve this?

Answer 1

You can use fun.data to apply a function ( f ) to the grouped data to return a count ( length(y) ) and a position for the label ( median(y) )

f <- function(y) 
    c(label=length(y), y=median(y))

library(ggplot2)
data(mtcars)
ggplot(mtcars, aes(x=as.factor(cyl), y=mpg)) +
  geom_boxplot() + theme_bw() +
  stat_summary(fun.data=f, geom="text", vjust=-0.5, col="blue")