R Booleans
R represents true and false with the logical type, which underlies every comparison you write and every condition you test.
The Logical Type
R represents true/false values with the reserved words TRUE and FALSE (or their shorthand T and F), stored under the type "logical". Comparisons such as ==, !=, <, >, <=, and >= all produce a logical value.
Example
is_active <- TRUE
class(is_active)
# "logical"
5 > 3
# TRUE
"cat" == "dog"
# FALSECombining Conditions
Use & and | to combine logical values element by element (handy inside vectors), and && / || to combine single conditions with short-circuit evaluation — stopping as soon as the answer is known — which is the form R recommends inside if() statements. ! negates a logical value.
Example
age <- 20
has_id <- TRUE
age >= 18 && has_id
# TRUE
!has_id
# FALSELogical Values Are Secretly Numbers
R treats TRUE as 1 and FALSE as 0 whenever a logical value is used in arithmetic, which makes sum() a quick way to count how many elements of a logical vector are TRUE.
Example
scores <- c(45, 82, 91, 60, 77)
passing <- scores >= 60
passing
# FALSE TRUE TRUE TRUE TRUE
sum(passing)
# 4Truth Tables at a Glance
Exercise: R Booleans
Why is it safer to write TRUE and FALSE in full rather than the shorthand T and F?
