ggplot - how to group observations into an 'other' category in the legend guide?

tidyverse
2

This is super-hacky and I'm sure there is a better way, but I think it works?!

library(tidyverse)

mtcars %>%
  mutate(
    car_name = rownames(mtcars),
    color = case_when(
      car_name == "Datsun 710" ~ "red",
      car_name == "Hornet 4 Drive" ~ "blue",
      TRUE ~ "gray"
      ),
    color = fct_relevel(color, "gray", after = Inf)
    ) %>% 
  head() %>% 
  ggplot() +
  geom_point(aes(x = mpg, y = disp, color = color)) + 
  scale_color_identity(
    labels = c(gray = "Other", red = "Datsun 710", blue = "Hornet 4 Drive"),
    guide = "legend"
    )

Created on 2020-06-08 by the reprex package (v0.3.0)