r - 将胡须末端放在箱线图上

Question

我想像boxplot函数自动给出的那样在胡须的末端放置垂直线。

Answer 1

正如@Roland 所暗示但未实现的那样，您可以使用它stat_boxplot来实现它。_boxplot两次调用的技巧是将其中一个调用设置geom为errorbar。

请注意，由于R使用笔和纸的方法，建议先实现误差线，然后在顶部绘制传统的箱线图。

使用@Roland 的虚拟数据df

ggplot(df, aes(x=cond, y = value))  + 
 stat_boxplot(geom ='errorbar') + 
 geom_boxplot() # shorthand for  stat_boxplot(geom='boxplot')

stat_boxplot( )的帮助?stat_boxplot详细说明了计算并保存在data.frame

Answer 2

要调整胡须线的大小，我们可以使用函数width = 0.5内部的参数：stat_boxplot

set.seed(42)
df <- data.frame(cond = factor(rep(c("A", "B"), each = 500)), 
                 value = c(rnorm(500, mean = 1, sd = 0.2), 
                           rnorm(500, mean = 1.5, sd = 0.1))) 

library(ggplot2)
ggplot(df, aes(x = cond, y = value)) +
       stat_boxplot(geom = "errorbar", width = 0.5) +  
       geom_boxplot() 

Answer 3

It might be possible to use stat_boxplot to calculate the whisker ends, but I am not enough of a ggplot2 wizard, so I use the base function for that.

set.seed(42)
df <- data.frame(cond = factor( rep(c("A","B"), each=500) ), 
                 value = c(rnorm(500,mean=1,sd=0.2),rnorm(500, mean=1.5,sd=0.1)))


whisk <- function(df,cond_col=1,val_col=2) {
  require(reshape2)
  condname <- names(df)[cond_col]
  names(df)[cond_col] <- "cond" 
  names(df)[val_col] <- "value"
  b <- boxplot(value~cond,data=df,plot=FALSE)
  df2 <- cbind(as.data.frame(b$stats),c("min","lq","m","uq","max"))
  names(df2) <- c(levels(df$cond),"pos")
  df2 <- melt(df2,id="pos",variable.name="cond")
  df2 <- dcast(df2,cond~pos)  
  names(df2)[1] <- condname
  df2
}



library(ggplot2)

plot1 <- ggplot(df, aes(x=cond)) 
plot1 <- plot1 + geom_errorbar(aes(ymin=min,ymax=max),data=whisk(df),width = 0.5)
plot1 <- plot1 + geom_boxplot(aes(y=value))
plot1