R中的边缘框图未按组对齐

Question

我有一个密度图，每个组具有不同的颜色，我想在顶部的每个组中添加一个边际箱线图。但是在盒图中，分组没有正确完成，都显示相同的数据。

set.seed(123)
library(ggplot2)
library(ggExtra)
library(data.table)
Data <- data.table(x = rnorm(100),
                   group = rep(c("group1", "group2"), times = c(30, 70)))
Data[group == "group1", x := x + 3]

p <-
  ggplot(Data, aes(x = x, fill = group, colour = group)) +
  geom_density(alpha = 0.5)

p %>% ggMarginal(type = "boxplot", 
                 margins = "x", 
                 size = 5,
                 groupColour = TRUE,
                 groupFill = TRUE)

更新： 使用geom_point可以正常工作：

p <-
  ggplot(Data, aes(x = x, y = x, fill = group, colour = group)) +
  geom_point(alpha = 0.5)

p %>% ggMarginal(type = "boxplot",
                 margins = "x",
                 size = 5,
                 groupColour = TRUE,
                 groupFill = TRUE)

那么，为什么它不能与geom_density一起使用？

Answer 1

如?ggMarginal的帮助文件中所述，该函数期望p中有一个ggplot2散点图。

以下将起作用：

p2 <- ggplot(Data, aes(x = x, fill = group, colour = group)) +
  geom_point(aes(y = 0.1), alpha = 0) + # add an invisible scatterplot geom as the first layer
  geom_density(alpha = 0.5)

p2 %>% ggMarginal(type = "boxplot", 
                 margins = "x", 
                 size = 5,
                 groupColour = TRUE,
                 groupFill = TRUE)