按组镜像直方图

Question

我想使用 ggplot按组获得镜像直方图，如下图所示。

library(ggplot2)
data2 <- data.frame(
  type = c( rep("Top 1", n_segment),
            rep("Top 2", n_segment),
            rep("Bottom 1", n_segment),
            rep("Bottom 2", n_segment)),
  value = c( rnorm(n_segment, mean=5),
             rnorm(n_segment, mean=12),
             rnorm(n_segment, mean=-5),
             rnorm(n_segment, mean=-12))
)

# Represent it
data2 %>%
  ggplot( aes(x=value, fill=type)) +
  geom_density( color="#e9ecef", alpha=0.6) 

现在我得到这个：

但我想将它们镜像如下：

Answer 1

尝试这种方法。您可以使用..density..和调整geom_density()数据的不同子集，启用data选项并智能过滤哪些值上升和下降。这里是代码：

library(ggplot2)
library(dplyr)
# Represent it
data2 %>%
  ggplot( aes(x=value, fill=type,group=type)) +
  geom_density(aes(y=-1*..density..),alpha=0.6,
               data = ~ subset(., type %in% c("Bottom 1","Bottom 2")))+
  geom_density(aes(y=..density..),alpha=0.6,
               data = ~ subset(., !type %in% c("Bottom 1","Bottom 2")))+
  ylab('density')

输出：

如果您想避免排队，请尝试以下操作：

# Represent it 2
data2 %>%
  ggplot( aes(x=value, fill=type,group=type)) +
  geom_density(aes(y=-1*..density..),alpha=0.6,color='transparent',
               data = ~ subset(., type %in% c("Bottom 1","Bottom 2")))+
  geom_density(aes(y=..density..),alpha=0.6,color='transparent',
               data = ~ subset(., !type %in% c("Bottom 1","Bottom 2")))+
  ylab('density')

输出：