R使用ggplot2获取2个图例

install.packages("ggplot2")

library(ggplot2)

data <- data.frame(x = c(1, 2, 3, 4, 5),
                   y1 = c(2, 4, 6, 8, 10),
                   y2 = c(1, 3, 5, 7, 9))

plot <- ggplot(data, aes(x = x))

plot <- plot + geom_line(aes(y = y1, color = "Line 1"))

plot <- plot + geom_line(aes(y = y2, color = "Line 2"))

plot <- plot + scale_color_manual(values = c("Line 1" = "red", "Line 2" = "blue"),
                                  labels = c("Line 1", "Line 2"))

plot <- plot + labs(color = "Legend Title")

print(plot)