Operators in R

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Arithmetic Operators

Addition

> 1 + 4

[1] 5

> 10 + 12

[1] 22

> sum(c(10, 15, 50))

[1] 75

Subtraction

> 4 - 1

[1] 3

> 10 - 12

[1] -2

Multiplication

> 10 * 3

[1] 30

> 1.5 * 2

[1] 3

> prod(c(1.5, 2))

[1] 3

Division

> 10/5

[1] 2

> typeof(10L/5L) # Division always returns double

[1] "double"

> 12/5

[1] 2.4

Exponent

Using "^"(), ^ or ** -

> "^"(2,3)

[1] 8

> 2^3

[1] 8

> 2**3

[1] 8

Modulus

To get the modulus or remainder from division use %% -

> 10%%4

[1] 2

> 24%%7

[1] 3

Integer Division

Using %/% get only the integers from a division -

> 10%/%4

[1] 2

> 24%/%7

[1] 3

Relational Operators

These operators returns a logical vector.

Less than, <

Single comparison -

> 10 < 11

[1] TRUE

> 11 < 10

[1] FALSE

Multiple comparison -

> x <- c(1, 5, 10, 12, 15, 6)
> x < 6  # Checks whether an element is less than 6 or not

[1]  TRUE  TRUE FALSE FALSE FALSE FALSE

Greater than, >

Single comparison -

> 10 > 11

[1] FALSE

> 11 > 10

[1] TRUE

Multiple comparison -

> x <- c(1, 5, 10, 12, 15, 6)
> x > 6  # Checks whether an element is greater than 6 or not

[1] FALSE FALSE  TRUE  TRUE  TRUE FALSE

Less than or equal to, <=

Single comparison -

> 10 <= 11

[1] TRUE

> 11 <= 11

[1] TRUE

> 11 <= 10

[1] FALSE

Multiple comparison -

> x <- c(1, 5, 10, 12, 15, 6)
> x <= 6  # Checks whether an element is less than or equal to 6 or not

[1]  TRUE  TRUE FALSE FALSE FALSE  TRUE

Greater than or equal to, >==

Single comparison -

> 10 >= 11

[1] FALSE

> 11 >= 11

[1] TRUE

> 11 >= 10

[1] TRUE

Multiple comparison -

> x <- c(1, 5, 10, 12, 15, 6)
> x >= 6  # Checks whether an element is greater than or equal to 6 or not

[1] FALSE FALSE  TRUE  TRUE  TRUE  TRUE

Equal to, ==

> x <- c(1, 5, 10, 12, 15, 6)
> x == 10  # Checks which element of the vector is equal to 10

[1] FALSE FALSE  TRUE FALSE FALSE FALSE

> which(x == 10)  # Returns the indexes of logical TRUE

[1] 3

> x == 10000  # Checks which element of the vector is equal to 10000

[1] FALSE FALSE FALSE FALSE FALSE FALSE

Not equal to, !=

> x <- c(1, 5, 10, 12, 15, 6)
> x != 10  # Checks which element of the vector is not equal to 10

[1]  TRUE  TRUE FALSE  TRUE  TRUE  TRUE

> which(x != 10)  # Returns the indexes of logical TRUE

[1] 1 2 4 5 6

AND, OR operators

Single comparison, || and &&

> x <- T
> y <- T
> x == T  && y == T  # Checks if both the two conditions are TRUE or not

[1] TRUE

> x <- T
> y <- F
> x == T  || y == T  # Checks if either one of the two conditions are TRUE or not

[1] TRUE

If the single operators are used for element-wise comparison then only the first pair/first element of the vector will be compared -

> x <- c(1, 5, 10, 12, 15, 6)
> # Checks if the first element is greater than or equal to 10 and less than or equal to 16
> x >= 10 || x <= 16  

[1] TRUE

Element-wise comparison, | and &

Element-wise AND operations can be performed using | -

> x <- c(1, 5, 10, 12, 15, 6)
> # Checks if the element is greater than or equal to 10 and less than or equal to 16
> x >= 10 & x <= 16  

[1] FALSE FALSE  TRUE  TRUE  TRUE FALSE

> which(x >= 10 & x <= 16)

[1] 3 4 5

OR operations can be performed using | -

> x <- c(1, 5, 10, 12, 15, 6)
> x == 10 | x == 6  # Checks if the element is equal to either 10 or 6

[1] FALSE FALSE  TRUE FALSE FALSE  TRUE

> which(x == 10 | x == 6)

[1] 3 6

%in%

A simpler way to perform element wise OR operations using %in% -

> x <- c(1, 5, 10, 12, 15, 6)
> x %in% c(6, 10)  # Checks if the element is equal to either 10 or 6

[1] FALSE FALSE  TRUE FALSE FALSE  TRUE

> which(x %in% c(6, 10))

[1] 3 6

NOT %in%

Using ! to invert the logical vector -

> x <- c(1, 5, 10, 12, 15, 6)
> !(x %in% c(6, 10))  # Checks if the element is not equal to either 10 or 6

[1]  TRUE  TRUE FALSE  TRUE  TRUE FALSE

> which(!(x %in% c(6, 10)))

[1] 1 2 4 5