Quickly Exploring Data - R Graphics - page 20

}
curve(myfun(x), from = 0 , to = 20 )
# Add a line:
curve( 1 - myfun(x), add = TRUE TRUE , col = "red" )

With the ggplot2 package, you can get a similar result using qplot() ( Figure 2-13 ), by using
stat="function" and geom="line" and passing it a function that takes a numeric vector as
input and returns a numeric vector:

library(ggplot2)
# This sets the x range from 0 to 20
qplot(c( 0 , 20 ), fun = myfun, stat = "function" , geom = "line" )
# This is equivalent to:
ggplot(data.frame(x = c( 0 , 20 )), aes(x = x)) + stat_function(fun = myfun, geom = "line" )

Figure 2-13. A function curve with qplot()