[R] na.rm = T treatment by ggplot2's geom_bar

[Dimitri Liakhovitski]

Hello!

I am trying to understand how ggplot2's geom_bar treats NAs.
The help file says:

library(ggplot2)
?geom_bar
na.rm: If FALSE, the default, missing values are removed with a warning. If
TRUE, missing values are silently removed.

I am trying it out:
md <- data.frame(a = c(letters[1:5], letters[1:4], letters[1:3], rep(NA,
3)))
str(md); levels(md$a)

ggplot(data = md, mapping = aes(x = a)) +
  geom_bar(na.rm = F)
It runs without warnings and generates counts for each factor level AS WELL
AS the NAs. Makes sense.

Now, I don't want the NAs to be counted. So, I run:
ggplot(data = md, mapping = aes(x = a)) +
  geom_bar(na.rm = T)

But I still have NAs in the picture. Why?
What am I missing?

Thank you!
-- 
Dimitri Liakhovitski

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