transfer numerical vector into color gradient

highlight.r

highlight <- function(x, colrange = c("black", "red2"), steps = NULL, range = "auto"){

if(is.null(steps)) steps = length(unique(x))
if(range[1] == "auto") {
	min_val = min(x, na.rm = TRUE)
	max_val = max(x, na.rm = TRUE)
	} else {
	min_val = range[1]
	max_val = range[2]
	}

colorscale <- colorRampPalette(colrange, space = "rgb")
cols <- colorscale( steps)

cols[as.integer((x-min_val)/(max_val-min_val)*steps+1)]

}