我使用facet_rep_grid来可视化同一x轴上的不同变量。现在我想用“A”，“B”，“C”等标记每个面的左上角。
我所拥有的看起来与此类似，但在单个方面之间的y轴上有更多差异：

library(dplyr)
library(ggplot2)
library(ggthemes)
library(lemon)
library(grid)
library(cowplot) 

# mpg dataset from ggplot2

mylabs <- c("facet 1", " facet 2", 'facet 3', 'facet 4')
names(mylabs) <- c(4,5,6,8)

ggplot(mpg,aes(x=year, y=hwy)) + 
  geom_point()+
  facet_rep_grid(cyl~., switch='y', scales="free", labeller=labeller(cyl=mylabs))+
  theme(strip.placement = "outside",
        strip.background = element_blank(),
        axis.title.y = element_blank())

字符串
我想要的是
image
我试着调整this，这将是好的“A”只。

ggplot(mpg,aes(x=year, y=hwy)) + 
  geom_point()+
  facet_rep_grid(cyl~., switch='y', scales="free", labeller=labeller(cyl=mylabs))+
  theme(strip.placement = "outside",
        strip.background = element_blank(),
        axis.title.y = element_blank())+
  
        labs(tag = "A/ only one") +
        coord_cartesian(clip = "off")

型
我还发现了this，但我无法将标签移动到绘图之外。

ggplot(mpg,aes(x=year, y=hwy)) + 
  geom_point()+
  facet_rep_grid(cyl~., switch='y', scales="free", labeller=labeller(cyl=mylabs))+
  theme(strip.placement = "outside",
        strip.background = element_blank(),
        axis.title.y = element_blank())+

  coord_cartesian(clip = "off")+
  geom_text(data = myLab, aes(x = -500, y = 10, label = mylabs), hjust =0)

型