Operators

Operators are special symbols that carry out some sort of computation. They can be applied to scalar quantities, vectors and matrices. Here are some commonly used operators:

Arithmetic:

Operator	Notation	Example
addition	+	x+y
multiplication	*	x*y
exponentiation	**	x**y

Logical:

Operator	Notation	Example
equal	==	x == y
not equal	!=	x != y
greater than or equal to	>=	x >= y
and	&	x>y & x>z
or	|	x>y | x>z

Figure: Complete set of boolean operations. x is the left-hand circle, y is the right-hand circle, and the shaded region show which parts each operator selects.

Example:

In this example, let’s go through a script in which the operators are used in combination. We are creating two vectors, x (1,2,3…10) and y (10,9,8…1). We would like to check two conditions using the operators:

AND: & If x is greater than y, and x is greater than 5, return TRUE. Both conditions must be met to return TRUE.

x <- 1:10
y <- 10:1 
x > y & x > 5 # Returns TRUE where both comparisons return TRUE.

OR: | We are checking a new condition now: If x is equal to y or x is not equal to y, return true. Either condition may be met to return TRUE.

x == y | x != y # Returns TRUE where at least one comparison is TRUE.