在ggplot2中手动为geom_path设置颜色，而不会影响绘图的其他元素

Question

鉴于下面的示例数据new_mtcars，对于基于变量geom_path为new_mtcars$group手动设置颜色的任何帮助，例如将black赋予{{1 }}和group1至red。

下面，我基于this answer展示我的失败尝试。问题是它根本不应用我要group2使用的颜色black和red。

＃准备样品数据

geom_path

＃创建群组

mtmodel <- lm(mpg ~ wt, data = mtcars)
mtcars$Low <- predict(mtmodel, newdata = mtcars, interval = "confidence")[,2]
mtcars$High <- predict(mtmodel, newdata = mtcars, interval = "confidence")[,3]
mtcars$Mean <- predict(mtmodel, newdata = mtcars, interval = "confidence")[,1]
new_mtcars<-tidyr::gather(mtcars, "Variable", "value", Low:Mean)

＃为geom_path自动选择颜色绘制绘图

library(tidyverse)
new_mtcars$group <- ifelse(new_mtcars$wt <= 3.5, "group1", "group2")
new_mtcars <- arrange(new_mtcars, wt)

＃我尝试根据组的级别手动设置geom_path的颜色

ggplot(new_mtcars, aes(x=wt, y=value, linetype=Variable)) +
  geom_path(size = 0.71, aes(colour = group)) +
  geom_point(aes(colour = cyl)) 

＃我当前的输出，该输出不会将所选颜色应用于geo_path

在此先感谢您的帮助。

Answer 1

这是一种依靠手动定义每种颜色的解决方案。我不知道一种只定义少数几个，剩下的要自动定义的方法。

ggplot(new_mtcars, aes(x=wt, y=value, linetype=Variable)) +
  geom_path(size = 0.71, aes(colour = group)) +
  # In the example, cyl was still numeric, creating an error here,
  #   since group is discrete and ggplot doesn't know how to mix
  #   discrete and continuous variables to the same aesthetic.
  geom_point(aes(colour = as.character(cyl)), shape = 21) +
  scale_color_manual(values = c("4" = "blue", "6" = "green", "8" = "purple", 
                                "group1" = "black", 
                                "group2" = "red"))