ggplot regression line and selected points

[startz]

I'd like to plot a regression line using ggplot and then add dots for a small subset of the observations, the latter selected by a particular column in my tibble being true. Probably obvious, but not to me at the moment.

Any advice gratefully received.

[technocrat]

library(ggplot2)
mtcars$four <- ifelse(mtcars$cyl == 4,TRUE,FALSE)
mtcars |> ggplot(aes(mpg,drat)) + 
  geom_point() +
  geom_smooth(method = "lm", se = FALSE) +
  theme_minimal()
#> `geom_smooth()` using formula = 'y ~ x'

mtcars |> ggplot(aes(mpg,drat)) + 
  geom_point(mapping = aes(color = four)) +
  geom_smooth(method = "lm", se = FALSE) +
  theme_minimal()
#> `geom_smooth()` using formula = 'y ~ x'

mtcars |> ggplot(aes(mpg,drat, color = four)) + 
  geom_point() +
  geom_smooth(method = "lm", se = FALSE) +
  theme_minimal()
#> `geom_smooth()` using formula = 'y ~ x'

^{Created on 2023-06-27 with reprex v2.0.2}

[startz]

Thanks @technocrat, but that's not quite what I want. I want one regression line done with all the data but the points shown only for four==TRUE.

[technocrat]

library(ggplot2)
mtcars$four <- ifelse(mtcars$cyl == 4, TRUE,FALSE)
ggplot(mtcars, aes(mpg,drat)) +
  geom_point(mapping = aes(color = ifelse(four, "red", NA))) +
  geom_smooth(method = "lm", se = FALSE) +
  scale_color_identity() +
  theme_minimal()
#> `geom_smooth()` using formula = 'y ~ x'
#> Warning: Removed 21 rows containing missing values (`geom_point()`).

[startz]

That is just so clever. Thanks.