Difference between scale_color_grey and scale_colour_grey in ggplot2

Question

What is the Difference between scale_color_grey and scale_colour_grey in ggplot2?

Color and Colour appear several times in ggplot2 . Is there a general rule for the difference between color and colour in ggplot2 ?

Answer 1

There is no difference concerning the code. British English vs. American English.

library(ggplot2)
identical(scale_colour_grey, scale_color_grey)
#[1] TRUE

Both are calling the same function:

> scale_color_grey
function (..., start = 0.2, end = 0.8, na.value = "red") 
{
    discrete_scale("colour", "grey", grey_pal(start, end), na.value = na.value, 
        ...)
}