is there a fucntion in R to colour code data points on regression of another column?

Question

I am trying to make a regression where there are points of two variables and they are colour coded based on another column that has "Yes" or "NO" in it.

Here is a random example with data I have made up, I hope this okay as I'm not sure how to make repeatable example.

km	litre	WOF
133	1	Yes
88	2	Yes
222	1	No

I have tried something like this by looking at lecture notes but it is not working.

cars <- read.csv("random_cardata.csv")

plot(km ~ litre, data = cars, pch = 19, col=c("black", "red")[car$WOF])

I am also trying to figure out how to make a legend where on the side it says:

"Green = has WOF" and 
"Red = no WOF"

Any help would be appreciated.

Answer 1

library(ggplot2)

data <- tibble::tribble(
  ~km, ~litre, ~WOF,
  133L, 1L, "Yes",
  88L, 2L, "Yes",
  222L, 1L, "No"
)

qplot(litre, km, color = WOF, data = data)

^{Created on 2022-03-30 by the reprex package (v2.0.0)}

or more comprehensive

library(tidyverse)

data <- tibble::tribble(
  ~km, ~litre, ~WOF,
  133L, 1L, "Yes",
  88L, 2L, "Yes",
  222L, 1L, "No"
)

data %>%
  mutate(WOF2 = ifelse(WOF == "Yes", "has WOF", "no WOF")) %>%
  qplot(litre, km, color = WOF2, data = .) + 
  scale_color_manual(values = c("has WOF" = "green", "no WOF" = "red")) +
  labs(color = "WOF")

^{Created on 2022-03-30 by the reprex package (v2.0.0)}