ggplot to display same colors for factor levels [duplicate]

Answer 1

Just use a named vector for MyPalette and scale_colour_manual():

MyPalette <- c(Fair = "#5DD0B9", Good = "#E1E7E9", "Very Good" = "#1f78b4", Premium =  "#a6cee3", Ideal = "#de77ae")

ggplot(diamonds2, aes(carat, price, color = cut)) + geom_point() +
  scale_colour_manual(values = MyPalette)

ggplot(diamonds3, aes(carat, price, color = cut)) + geom_point() +
  scale_colour_manual(values = MyPalette)