How can I set the colour for a single data point in a scatter plot in R?
I am using plot
To expand on @Dirk Eddelbuettel's answer, you can use any function for col in the call to plot. For instance, this colors the x==3 point red, leaving all others black:
x <- 1:5
plot(x, x, col=ifelse(x==3, "red", "black"))

Same goes for point character pch, character expansion cex, etc.
plot(x, x, col=ifelse(x==3, "red", "black"),
pch=ifelse(x==3, 19, 1), cex=ifelse(x==3, 2, 1))
