r - 在ggplot2中结合图例

Question

我有多个 geom_point 的情节和一个stat_function在 ggplot2 .有没有办法显示单个图例？

df <- data.frame("x"=c(1:5), "a"=c(1,2,3,3,3), "b"=c(1,1.1,1.3,1.5,1.5))
df <- melt(df, "x")
p <- ggplot(df, aes(x=x, y=value)) +
  geom_point(aes(colour=variable, shape=variable)) +
  stat_function(aes(colour="log2(x)"), fun=log2)

我想要一个带有蓝线和两种颜色形状的图例。我试过

scale_colour_discrete(name="legend", breaks=c("a", "b", "log2(x)")) +
scale_shape_discrete(name="legend", breaks=c("a", "b"))

但这不起作用。有没有办法自动或手动执行此操作？

提前致谢。

Answer 1

可能更简单的替代方法是使用 override.aes如下:

ggplot(df, aes(x = x, y = value)) +
  geom_point(aes(colour = variable, shape = variable), size = 3) +
  stat_function(aes(colour = "log2(x)"), fun = log2, size = 1.5) +
  guides(shape = FALSE,
         colour = guide_legend(override.aes = list(shape = c(16, 17, NA),
                                                   linetype = c("blank", "blank", "solid"))))

这导致: