How do I generate a mapping from numbers to colors in R?

Question

In R, I can easily generate a color ramp, for example colorRampPalette. The following produces a sequence of five colors, from blue to red:

> mypal <- colo         


        

Answer 1

The simplest thing I can think of is discretizing your variable x with cut and then using the resultant factor to index a color Palettes like heat.colors or cm.colors

f <- function(x,n=10){
    heat.colors(n)[cut(x,n)]
}

see ?heat.colors for more details of Palettes.

This function will give you are color vector corresponding to x of varying granularity proportional to n.