Plot two graphs in same plot in R

Question

I would like to plot y1 and y2 in the same plot.

x  <- seq(-2, 2, 0.05) y1 <- pnorm(x) y2 <- pnorm(x, 1, 1) plot(x, y1, type = "l", col = "red") plot(x, y2, type = "l", col = "green") 

But when I do it like this, they are not plotted in the same plot together.

In Matlab one can do hold on, but does anyone know how to do this in R?

Answer 1

lines() or points() will add to the existing graph, but will not create a new window. So you'd need to do

plot(x,y1,type="l",col="red") lines(x,y2,col="green") 

Answer 2

You can also use par and plot on the same graph but different axis. Something as follows:

plot( x, y1, type="l", col="red" ) par(new=TRUE) plot( x, y2, type="l", col="green" ) 

If you read in detail about par in R, you will be able to generate really interesting graphs. Another book to look at is Paul Murrel's R Graphics.