Combining "vline" and "hline" statements together

[omario]

Recently, I learned how to "draw" horizontal and vertical lines with the ggplot2 library:

library(ggplot2)

# Simple scatter plot
sp <- ggplot(data=mtcars, aes(x=wt, y=mpg)) + geom_point()

# Add horizontal line at y = 2O

a = sp + geom_hline(yintercept=20) 

b = sp + geom_vline(xintercept = 3)

Now, I am trying to combine these statements together - for example:

c = sp + geom_hline(yintercept=20) +  geom_hline(yintercept=15) + geom_vline(xintercept = 3) +
    geom_vline(xintercept = 5) + geom_vline(xintercept = 6) + geom_hline(yintercept=35)

Question: I am trying to modify the above plot so that it looks like this:

[

]

Can someone please show me how to do this? Or do you have to manually export this plot into Microsoft Paint and change it over there?

Thanks

[FJCC]

Here is one solution.

library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 4.0.5

LINES <- data.frame(Startx=c(1,1,1,3,5,6),#horiz lines then vert lines
                    Starty=c(15,20,35,7,7,7),
                    Endx=c(3,5,6,3,5,6),
                    Endy=c(15,20,35,15,20,35))
ggplot(data=mtcars, aes(x=wt, y=mpg)) + geom_point()+
  geom_segment(aes(x=Startx,y=Starty,xend=Endx,yend=Endy),data=LINES)+
  coord_cartesian(ylim=c(9,36),xlim = c(1.5,6.2))#set limits tighter than line ends

^{Created on 2021-08-14 by the reprex package (v0.3.0)}