r - 用颜色向量突出显示 ggplot2 中的前 3 个

Question

我有一个下面的代码，我想用选定的颜色为前 3 个着色。非常感谢。

    library(ggplot2)
library(dplyr)

df <- data.frame(dose = c("D0.5", "D1", "D2", "D3", "D4", "D5"),
                 len = c(4.2, 10, 29.5, 5, 7, 15))

df <- dplyr::mutate(df, top3 = rank(-len) %in% 1:3)


# Basic barplot
p <- ggplot(data = df, aes(x = reorder(dose, -len), y = len)) +
  geom_bar(stat = "identity", fill = ifelse(df$top3 == TRUE,  c("blue", "yellow", "green"), "grey50")) + 
           #color = ifelse(df$top3 == TRUE,  c("red", "yellow", "green"), "grey50")) +
  coord_flip()
p

Answer 1

你可以这样做:

df <- data.frame(dose = c("D0.5", "D1", "D2", "D3", "D4", "D5"),
                 len = c(4.2, 10, 29.5, 5, 7, 15))

df <- df |> 
  dplyr::arrange(desc(len)) |>
  dplyr::mutate(
    rank = factor(dplyr::row_number(), labels = dose)
  )

fill_colors = c("blue", "yellow", "green")
other_colors = rep("grey50", nrow(df)-length(fill_colors))
my_scale  <- c(fill_colors, other_colors)

withr::with_options(
  list(ggplot2.discrete.fill = my_scale),
  ggplot(data = df, aes(x = reorder(dose, -len), y = len)) +
  geom_bar(stat = "identity", aes(fill = rank)) +
  scale_fill_discrete() +
  coord_flip()
)