ggplot: remove NA factor level in legend

Question

How can I omit the NA level of a factor from a legend?

From the nycflights13 database, I created a new continuous variable called

Answer 1

I like @Artem's method above, i.e., getting to the bottom of why there are NA's in your df. However, sometimes you know there are NA's, and you just want to exclude them. In that case, simply using 'na.omit' should work:

na.omit(flights) %>% ggplot() +
geom_bar(mapping = aes(x = carrier, fill = delay_class), position = "fill")