how to create a plot with customized points in R?

Question

I know I can create a plot with line and dots using the type = \"o\" argument in the plot command. I would like some more control over this -- I want to be able to draw the

Answer 1

You could use layering (I don't work in base too much any more as a social researcher I love the facet_grid of ggplot, so there may be a better way) as in:

x <- sort(rnorm(25))
y <- sort(rnorm(25))
z <- as.factor(sample(LETTERS[1:5], 25, r=TRUE))

plot(x, y, pch = 19, cex = 1.3)
par(new = TRUE)
plot(x, y, pch = 19, cex = 1, col = z)

Which gives you: