Logical Operators

Overview

Logical operators are symbols that can be used within R to compare values or vectors of values.

Operator Description

<

less than

⇐

less than or equal to

>

greater than

>=

greater than or equal to

==

equal to

!=

not equal to

!x

negation, not x

x|y

x OR y

x&y

x AND y

Examples

Given a vector, vec, get a vector of logical values indicating whether the values are greater than 5 (TRUE), or not (FALSE).

Solution
vec <- 1:10
vec > 5
[1] FALSE FALSE FALSE FALSE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE

Given a vector, vec, get a vector of logical values indicating whether the values are greater than or equal to 5 (TRUE), or not (FALSE).

Solution
vec <- 1:10
vec >= 5
[1] FALSE FALSE FALSE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE

Given a vector, vec, get a vector of logical values indicating whether the values are less than 5 (TRUE), or not (FALSE).

Solution
vec <- 1:10
vec < 5
[1]  TRUE  TRUE  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE

Given a vector, vec, get a vector of logical values indicating whether the values are less than or equal to 5 (TRUE), or not (FALSE).

Solution
vec <- 1:10
vec <= 5
[1]  TRUE  TRUE  TRUE  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE

Given a vector, vec, get a vector of logical values indicating whether the values that are greater than 7 or less than or equal to 2 (TRUE), or not (FALSE).

Solution
vec <- 1:10
vec > 7 | vec <=2
[1]  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE  TRUE  TRUE  TRUE

Given a vector, vec, get a vector of logical values indicating whether the values that are greater than 3 and less than 6 (TRUE), or not (FALSE).

Solution
vec <- 1:10
vec > 3 & vec < 6
[1] FALSE FALSE FALSE  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE

Given vectors vec1 and vec2, get the values that are in vec1 that are also in vec2.

Solution
vec1 <- c("this", "is", "a", "test")
vec2 <- c("this", "a", "exam")
vec1[vec1 %in% vec2]
[1] "this" "a"

Given vectors vec1 and vec2, get the values that are in vec1 that are not in vec2.

Solution
vec1 <- c("this", "is", "a", "test")
vec2 <- c("this", "a", "exam")
vec1[!(vec1 %in% vec2)]
[1] "is" "test"

Given a vector, vec, get the number of values in vec that are greater than 5.

Solution
vec <- 1:10
sum(vec>5)
[1] 5
# note, you do not need to do
length(vec[vec>5])
[1] 5
# because TRUE==1 and FALSE==0 in R
TRUE==1
[1] TRUE
FALSE==0
[1] TRUE

Resources

Operators Summary

A quick list of the various operators with a few simple examples.