What's the meaning of this exclamatory sign (!) in R language?

Question

I don't understand the use of exclamatory signs here.

x <- [!x %in% boxplot(x)$out]

Just fyi you can search for help on pretty much all operators. `help("!")` or `?\`!\``. — Ritchie Sacramento, Sep 07 '21 at 10:31
Have a look at [Opposite of %in%: exclude rows with values specified in a vector](https://stackoverflow.com/q/5831794/10488504) — GKi, Sep 07 '21 at 10:45
Try the simple `! TRUE` , which returns `FALSE`. It can not get clearer than that — GuedesBF, Sep 07 '21 at 11:08

score 2 · Answer 1 · answered Sep 07 '21 at 10:34

! is nothing more than just a negation.

You should start from %in% if the example you gave is problematic for you.

vector1 <- c("a", "b")

vector2 <- c("c", "a")

vector1 %in% vector2 # for each element of vector1 do: is it in vector2?
#> [1]  TRUE FALSE

if you use ! now, i.e. negate the output, you will get:

!vector1 %in% vector2
#> [1] FALSE  TRUE

1 Answers1