ggplot2中geom_segment函数的用法

 

1、

> coor <- data.frame( x = c(3,4,5),y = c(10,20,30), 
+                    xend = c(2.5,3.5,4.5), yend = c(20,30,10))
> coor
  x  y xend yend
1 3 10  2.5   20
2 4 20  3.5   30
3 5 30  4.5   10
> ggplot(mtcars, aes(x = drat, y = mpg)) + geom_line() + 
+   geom_segment(data = coor, aes(x = x, y = y, xend = xend, yend = yend),
+                lty = 1, colour = "red")