r - ggplot 中不同几何图形的 scale_color_manual()

Question

library(tidyverse)

delta <- tibble(
  type = c("alpha", "beta", "gamma"), 
  a = rnorm(3, 5), 
  b = rnorm(3, 6)
  ) %>% 
  mutate(delta = abs(a - b)) %>% 
  gather(`a`, `b`, `delta`, key = "letter", value = "value")


ggplot(delta %>% filter(letter != "delta"), aes(type, value, fill = letter)) +
  geom_col(position = "dodge") + 
  geom_col(data = delta %>% filter(letter == "delta"), width = 0.5) + 
  scale_color_manual("grey", "black", "blue")

我希望 a 和 b 条为灰色和黑色。 delta 条为蓝色。如何使用 scale_color_manual() 做到这一点？看来我上面的语法是关闭的。

Answer 1

有两处需要修改:

1. 既然您使用了 fill = letter，您应该使用 scale_fill_manual 而不是 scale_color_manual(如果你使用了 color = letter)。

2. 手动颜色值应作为向量提供。

library(tidyverse)

delta <- tibble(
  type = c("alpha", "beta", "gamma"), 
  a = rnorm(3, 5), 
  b = rnorm(3, 6)
) %>% 
  mutate(delta = abs(a - b)) %>% 
  gather(`a`, `b`, `delta`, key = "letter", value = "value")


ggplot(delta %>% filter(letter != "delta"), aes(type, value, fill = letter)) +
  geom_col(position = "dodge") + 
  geom_col(data = delta %>% filter(letter == "delta"), width = 0.5) + 
  scale_fill_manual(values = c("grey", "black", "blue"))

^{由 reprex package 创建于 2018-10-08 (v0.2.1)}