r - 如何自定义向ggplot facet函数添加垂直线？

Question

我有一个数据集，其中每个物种都与另一个物种的特定密度(数字)和类型(数字)混合。我想向 ggplot 中的每个 facet_grid 面板添加两种类型的垂直线:
(a) 潜水密度/类型的固定线路。例如1000/1 = 1000, 1000/6 = 166.7, 10000/1 = 10000, 10000/6 = 1666.7
(b) 叠加在直方图上的每个处理的自举平均和置信区间。
我尝试使用 geom_vline 添加平均值，但似乎不对。看起来所有的手段都是一样的

set.seed(111)
count <- rbinom(500,100,0.1) 
species <- rep(c("A","B"),time = 250)
density <- rep(c("1000","10000","1000","10000"),time = 125)
type <- rep(c("1","1","6","6"),time = 125)
df <- data.frame(species, density, type, count) # I feel too naiive, but I'm not able to get all the treatments filled. Gah.

ggplot(df, aes(x= count, colour = species, fill = species)) + 
   geom_histogram(position="identity", alpha=0.5) + 
   theme_bw() + ylab("Frequency") + 
   facet_grid(species ~ type + density) + 
   theme(panel.grid.major = element_blank(),
         panel.grid.minor = element_blank()) +
   theme(legend.position = "none") + theme(aspect.ratio = 1.75/1) + 
   geom_vline(aes(xintercept=mean(count)),color="blue", linetype="dashed", size=1)

Answer 1

我不确定为什么这是分面的默认行为，但我认为它的方法是将汇总数据传递给 geom_vline .一种方法如下(在最后一学期更改您的代码)...

ggplot(df, aes(x= count, colour = species, fill = species)) + 
  geom_histogram(position="identity", alpha=0.5) + 
  theme_bw() + ylab("Frequency") + 
  facet_grid(species ~ type + density) + 
  theme(legend.position = "none") + theme(aspect.ratio = 1.75/1) + 
  geom_vline(data = function(x) x %>% 
               group_by(species, type, density) %>% 
               summarise(meancount = mean(count)),
             aes(xintercept=meancount),color="blue", linetype="dashed", size=1)

(我已经恢复了网格线，以便您可以看到该线确实移动了一点!)