是否有仅显示图例键子集的 R 函数？

Question

基于我之前的问题，感谢@AndrewGB 对代码的修改 ()，我有一个包含 24 个柱的数据集（状态为 high/low 的各个类别）。

在我的类别中，我有一个类别类型，这意味着我只需要显示图例键的一个子集（即，仅显示唯一颜色）。在我提供的玩具数据中，它类似于“Plant Type A”（粉红色）和“Plant Type B”（蓝色）以及“Control”（灰色）。

我的预期输出是仅绘制独特的图例颜色，然后为这些键提供可自定义的标签。

library(ggplot2)
library(data.table)

dat <- as.data.table(cbind(iris, Status = rep(c("High", "Low"), 75)))
dat <- rbind(dat, data.frame(Petal.Width = sample(iris$Petal.Width, 30, replace = T),
      Species = "Control", 
      Status = "Control"), fill = T)

ggplot(dat, aes(x = Species,y = Petal.Width, fill = Status)) +
  geom_boxplot(position = position_dodge(width = 0.9)) +
  scale_fill_manual(values = c("red", "pink",
                               "red", "pink",
                               "blue", "slateblue", "grey"))

ggplot(dat, aes(x = Species, y = Petal.Width, fill = interaction(Status,Species))) +
  geom_boxplot(position = position_dodge(width = 0.9)) +
  scale_fill_manual(values = c("red", "pink",
                               "red", "pink",
                               "blue", "slateblue", "grey"))

传说将是：

Plant Type A: High Status (red)
Plant Type A: Low Status (pink)
Plant Type B: High Status (blue)
Plant Type B: Low Status (slateblue)
Control - no status (grey)

我研究了 override.aes、guides 和 scale_fill_manual - breaks，但如果不弄乱绘制的颜色，似乎无法使它正常工作。

Answer 1

您可以使用 scale_fill_manual 的 breaks 参数来限制图例条目的数量，而不限制实际绘制的颜色。但是，您需要在 values 参数中明确命名颜色：

library(tidyverse)
library(data.table)
#> 
#> Attaching package: 'data.table'
#> The following objects are masked from 'package:dplyr':
#> 
#>     between, first, last
#> The following object is masked from 'package:purrr':
#> 
#>     transpose

dat <- as.data.table(cbind(iris, Status = rep(c("High", "Low"), 75)))
dat <- rbind(dat, data.frame(
  Petal.Width = sample(iris$Petal.Width, 30, replace = T),
  Species = "Control",
  Status = "Control"
), fill = T)

dat %>%
  mutate(fill = Species %>% paste0(Status)) %>%
  ggplot(aes(x = Species, y = Petal.Width, fill = fill)) +
  geom_boxplot() +
  scale_fill_manual(
    values = c(
      setosaHigh = "red", setosaLow = "pink",
      versicolorHigh = "lightgreen", versicolorLow = "darkgreen",
      virginicaHigh = "darkblue", virginicaLow = "lightblue",
      ControlControl = "purple"
    ),
    breaks = c("virginicaLow", "virginicaHigh", "ControlControl")
  )

^{由 reprex package (v2.0.0)}

于 2022-05-10 创建

是否有仅显示图例键子集的 R 函数？

Is there an R function for displaying only a subset of legend keys?

r

ggplot2

boxplot

legend-properties