使用颜色矢量突出显示 ggplot2 中的前 3 名

Question

我在下面有一个代码，我想用选定的颜色为前 3 个颜色上色。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()
)

Answer 2

您可以在数据框中添加一个额外的颜色排名列，并根据 scale_fill_manual:

更改颜色

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))
df <- dplyr::mutate(df, col_rank = as.character( ifelse(top3 > 3, 4, top3)))

# Basic barplot
p <- ggplot(data = df, aes(x = reorder(dose, -len), y = len, fill = col_rank)) +
  geom_bar(stat = "identity") + 
  coord_flip() +
  scale_fill_manual(values = c("1" = "blue", "2" = "yellow", "3" = "green", "4" = "grey50"))
p

Answer 3

与其他建议的选项略有不同，代码更少。我认为您对 if else 语句的想法通常是可以的 - 但是，您在 aes 中使用 $ 似乎很危险。我们可以这样做的原因是顶行的数量与颜色向量的长度相匹配（在这种情况下：3）

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))

mycols <- c("blue", "yellow", "green")

df <- df %>%
  arrange(desc(len)) %>%
  mutate(fills = ifelse(row_number() <= length(mycols), mycols, "grey50"))

## swapping x and y makes coord_flip obsolete
## using I in aes is the same as adding "scale_fill_identity" at the end
ggplot(data = df, aes(x = len, y = reorder(dose, -len))) +
  geom_col(aes(fill = I(fills)))

^{由 reprex package (v2.0.1)}

于 2022-05-30 创建

使用颜色矢量突出显示 ggplot2 中的前 3 名

Highlight top 3 in ggplot2 with vector of colors

r

ggplot2