在ggplot中按类着色垂直线

Question

我想用Class绘制变量的分布，并添加垂直线，表示每个Class定义的子集的平均值，并按类着色。当我成功按类对颜色分布进行着色时，垂直线显示为灰色。有关可重复的示例，请参阅以下内容：

library(data.table)
library(ggplot2)
library(ggthemes)

data(mtcars)
setDT(mtcars)
mtcars[, am := factor(am, levels = c(1, 0))]
mean_data <- mtcars[, .(mu = mean(hp)), by = am]

ggplot(mtcars, aes(x = hp, fill = am , color = am)) +
  geom_histogram(aes(y=..density..), position="identity",alpha = 0.4) + guides(color = FALSE) +
  geom_density (alpha = 0.5)+ 
  geom_vline(data = mean_data, xintercept = mean_data$mu, aes(color = as.factor(mean_data$am)), size = 2, alpha = 0.5) +
  ggtitle("Hp by am") + scale_fill_discrete(labels=c("am" , "no am")) +
  labs(fill = "Transmission") + theme_economist()

此代码呈现以下图：

您的建议将不胜感激。

Answer 1

您需要在xintercept来电中加入aes映射，以便ggplot正确映射所有美学：

ggplot(mtcars, aes(x = hp, fill = am , color = am)) +
    geom_histogram(aes(y=..density..), position="identity",alpha = 0.4) + guides(color = FALSE) +
    geom_density (alpha = 0.5)+ 
    geom_vline(data = mean_data, aes(xintercept = mu, color = as.factor(am)), size = 2, alpha = 0.5) +
    ggtitle("Hp by am") + scale_fill_discrete(labels=c("am" , "no am")) +
    labs(fill = "Transmission") + theme_economist()

geom来自aes不在marshmallow_enum的电话中的任何内容都会被视为一次性价值，而且并未获得应用于其中的所有映射美学。