结合不同长度的数据帧中的ggplots

Question

我有两个来自不同长度的数据帧的 ggplots，我分别绘制了一列的直方图，如下所示。我想将这两个图组合成一个具有两个不同 y 轴的 ggplot，一个在右侧，一个在左侧，用于两个数据帧。我该怎么做？

a = ggplot(GG, aes(x = as.numeric(Kstat))) +
  theme_pubclean()

a + geom_density() +
  geom_vline(aes(xintercept = mean(Kstat)), 
             linetype = "dashed", size = 0.6) + xlim(0,1000)+ylim(0,0.1)

b = ggplot(all, aes(x = as.numeric(Kstat))) +
  theme_pubclean()

b + geom_density() +
  geom_vline(aes(xintercept = mean(Kstat)), 
             linetype = "dashed", size = 0.6) + xlim(0,1000)+ylim(0,0.5)

Answer 1

我们没有你的数据，所以这里有一个包含在ggplot2 中的数据集的示例：

library(ggplot2)
df1 <- diamonds[1:10,7]
df2 <- diamonds[100:2100,7]

对于本例，df1 中的数据变化不大，因此密度峰值大约高出 25 倍。

ggplot() +
  geom_density(data = df1, aes(x = price)) +
  geom_vline(data = df1, aes(xintercept = mean(price)), 
             linetype = "dashed", size = 0.6) +
  geom_density(data = df2, aes(x = price), color = "red") +
  geom_vline(data = df2, aes(xintercept = mean(price)), 
             linetype = "dashed", color = "red", size = 0.6) 

解决此问题的一种方法是将 df2 密度放大 25 倍，并通过反向调整创建辅助轴。 （这就是 ggplot2 中辅助轴的工作方式；您首先将数据缩放到主轴上，然后创建辅助轴作为帮助读者理解它的注释。）

ggplot() +
  geom_density(data = df1, aes(x = price)) +
  geom_vline(data = df1, aes(xintercept = mean(price)), 
             linetype = "dashed", size = 0.6) +
  geom_density(data = df2, aes(x = price, y = ..density.. * 25), color = "red") +
  geom_vline(data = df2, aes(xintercept = mean(price)), 
             linetype = "dashed", color = "red", size = 0.6) +
  scale_y_continuous(sec.axis = ~ . / 25) +
  theme(axis.text.y.right = element_text(color = "red"))