怎么样:
(首先创建一个可重现的示例)
set.seed(1001)
lengths <- data.frame(length=c(rgamma(1000,shape=10,scale=500),
10000+rgamma(1000,shape=5,scale=700),
rnorm(500,mean=30000,sd=2000)),
library=factor(rep(2:1,c(2000,500))))
(寻找峰值位置和高度的可爱东西)
peakfun <- function(x) {
d <- density(x$length)
peaks <- which(diff(sign(diff(d$y)))==-2)
data.frame(x=d$x[peaks],y=d$y[peaks])
}
peakdat <- ddply(lengths,.(library),peakfun)
peakdat <- peakdat[-1,] ## drop spurious peak
(绘制情节)
library(ggplot2)
ggplot(lengths, aes(length, fill = library)) +
geom_density(alpha = 0.2) +
scale_x_continuous(limits = c(0,60000),
breaks = seq(0,60000,by=5000))+
geom_text(data=peakdat,aes(x=x,y=y,label=round(x)),vjust=1)
您可能想稍微调整标签的垂直高度