将线条添加到现有的 ggplot 并在图例中获取它们

Question

我正在尝试为已添加到现有 ggplot 的行添加一个键。

设置：

test.mat <- data.frame(matrix(nrow=32, ncol =3))
test.mat[,1] = rep(1:16,2)
test.mat[1:16,2] = as.character(rep("Cohort Alpha"),16)
test.mat[17:32,2] = as.character(rep("Factor Alpha"), 16)
test.mat[,3] = rnorm(32,0,1)
colnames(test.mat) = c("Window", "type", "value")

ggplot(test.mat, aes(x=Window, y=value, size = type)) +
  geom_line(aes(colour = type, linetype = type)) +
  scale_colour_manual("type", values = c("black", "steelblue")) +
  scale_linetype_manual("type", values = c("solid", "solid")) +
  scale_size_manual("type", values = c(0.8, 1.4), guide = "none") +
  xlab("Quarter after alpha assessment") + ylab("t-statistics") + ggtitle("Panel Regression t-statistics") +  theme_classic() + 
  theme(
    text = element_text(family = "Times New Roman"),
    plot.title = element_text(color = "black", size = 12, hjust = 0.5),
    axis.title = element_text(size = 12),
    legend.title = element_blank()) +
    geom_hline(yintercept = 1.282 , color = "dark green") +
    geom_hline(yintercept = 1.645 , color = "dark grey") +
    geom_hline(yintercept = 2.326 , color = "grey")

我想要标记为“*”的深绿色线，我想要标记为“**”的深灰色线，并且我想要标记为“***”的灰色线。我希望这些标签出现在图例中。

Answer 1

您可以在geom_hline 和aes 中使用linetype，以便将这些行包含在图例中。我更改了scale_linetype_manual，所以它会反映新图例线条的颜色。这是你的想法吗？

library(ggplot2)

set.seed(1)

test.mat <- data.frame(matrix(nrow=32, ncol =3))
test.mat[,1] = rep(1:16,2)
test.mat[1:16,2] = as.character(rep("Cohort Alpha"),16)
test.mat[17:32,2] = as.character(rep("Factor Alpha"), 16)
test.mat[,3] = rnorm(32,0,1)
colnames(test.mat) = c("Window", "type", "value")

ggplot(test.mat, aes(x=Window, y=value, size = type)) +
  geom_line(aes(colour = type)) +
  scale_colour_manual("type", values = c("black", "steelblue")) +
  scale_size_manual("type", values = c(0.8, 1.4), guide = "none") +
  xlab("Quarter after alpha assessment") + ylab("t-statistics") + ggtitle("Panel Regression t-statistics") +  theme_classic() + 
  theme(
    text = element_text(family = "Times New Roman"),
    plot.title = element_text(color = "black", size = 12, hjust = 0.5),
    axis.title = element_text(size = 12),
    legend.title = element_blank()) +
  geom_hline(aes(linetype = "*", yintercept = 1.282), color = "dark green") +
  geom_hline(aes(linetype = "**", yintercept = 1.645), color = "dark grey") +
  geom_hline(aes(linetype = "***", yintercept = 2.326), color = "grey") +
  scale_linetype_manual("sig", values = c("solid", "solid", "solid"),
                        guide = guide_legend(override.aes = list(color=c("dark green", "dark grey", "grey"))))