r - ggplot2 为几个 stat_functions 添加图例

Question

我看到很多关于如何自定义图例的问题，但我什至无法自定义图例。我想有一个图例来解释黑线是二次方，绿线是三次方。

library(ggplot2)

myfun1 <- function(x) x^2
myfun2 <- function(x) x^3

myplot <- ggplot(data = data.frame(x = 1:5, y= 1:5), aes(x=x, y=y)) +
    stat_function(fun = myfun1, color="green") +
    stat_function(fun = myfun2, color="black")

Answer 1

试试这个:

ggplot(NULL, aes(x=x, colour = g)) +
  stat_function(data = data.frame(x = 1:5, g = factor(1)), fun = myfun1) +
  stat_function(data = data.frame(x = 1:5, g = factor(2)), fun = myfun2) +
  scale_colour_manual(values = c("red", "green"), labels = c("quadratic", "cubic"))