How can I negate a logical value in a base R pipeline?

Question

Running

TRUE |> `!`()

Results in:

Error in !NULL : 
  function '!' not supported in RHS call of a pipe (<input>:1:9)

When using magrittr, there is a not() alias, but this does not work for base R. See: Negation `!` in a dplyr pipeline `%>%`

Answer 1

Simply adding brackets:

TRUE |> (`!`)()
#[1] FALSE

Answer 2

Negate()

One base R approach is to Negate() the identity() function:

TRUE |> Negate(identity)()
# [1] FALSE

This is parsed as Negate(identity)(TRUE), i.e. !TRUE.

isFALSE()

Alternatively, you can use isFALSE(), though this is limited to vectors of length one:

TRUE |> isFALSE()
# [1] FALSE

If you have a longer logical vector, v, you can *apply() this function. It's important to be aware that this is stricter than Negate(), both in terms of how it handles NA and how it treats other truthy/falsy values:

# NA values
v <- c(TRUE, NA, FALSE)
v |> Negate(identity)()
# [1] FALSE    NA  TRUE
v |> sapply(isFALSE)
# [1] FALSE FALSE  TRUE

# Other falsy values e.g. 0 handled differently
0  |> Negate(identity)()
# [1] TRUE
0  |> isFALSE()
# [1] FALSE

This is explicit, but whether its treatment of NA is desired will depend on your goal.

xor()

Finally, if you want to be perhaps a little too clever about it, you can use xor(), taking advantage of the fact that xor(x, TRUE) is equivalent to !x, because:

x	y	xor(x, y)
FALSE	TRUE	TRUE
TRUE	TRUE	FALSE

v <- c(TRUE, NA, FALSE)
v |> xor(TRUE)
# [1] FALSE    NA  TRUE
identical(v |> xor(TRUE), !v)
# [1] TRUE