使用ggplot2躲避箱形图和错误栏

Question

library(ggplot2)
library(Hmisc)
data(mtcars)
myplot <- ggplot(mtcars, aes(x = as.factor(cyl), y = qsec)) +
    geom_boxplot() +
    stat_summary(fun.y = mean, geom = "point", shape = 5, size = 2) +
    stat_summary(fun.data = mean_cl_normal, geom = "errorbar",
             width = 0.2)

产生

我想将平均值和误差条略微偏向右侧，这样误差条就不会遮挡箱线图的IQR线。指定position=position_dodge(.5)不会似乎无效，因为geom_errorbar不了解geom_boxplot。

Answer 1

您可以引入一个新变量，用作错误栏的x偏移量：

library(ggplot2)
library(Hmisc)
data(mtcars)
mtcars$cyl.n <- as.numeric(as.factor(mtcars$cyl)) + .5

(myplot <- ggplot(mtcars, aes(x = as.factor(cyl), y = qsec)) +
    geom_boxplot() +
    stat_summary(aes(x = cyl.n), fun.y = mean, geom = "point", shape = 5, size = 2) +
    stat_summary(aes(x = cyl.n), fun.data = mean_cl_normal, geom = "errorbar",
           width = 0.2))

as.numeric(as.factor(.))确保新的错误条与箱图的位置相同但移动了0.5个单位。