问使用geom_boxplot()更改整齐数据帧中箱图的顺序

EN

cats = c("cat1", "cat2", "cat3", "cat4")
df = tibble(a = rnorm(100), b = rep(cats, 25))

library(dplyr)
position <- df %>% group_by(b) %>% summarise(median=median(a)) %>% 
  arrange(desc(median)) %>% pull(b)

df$b <- factor(df$b,levels=position)
# order_wanted <- c(2,1,4,3)
# levels(df$b) <- paste0("cat",order_wanted)

library(ggplot2)
ggplot(data = df) + geom_boxplot(aes(x = b, y = a, fill = b))