Data Infix Operators in R

Intro to Infix Operators in R

Infix operators in R are unique functions and methods that facilitate basic data expressions or transformations.  

Infix refers to the placement of the arithmetic operator between variables.  For example, an infix operation is given by (a+b), whereas prefix and postfix operators are given by (+ab) and (ab+), respectively.  

The types of infix operators used in R include functions for data extraction, arithmetic, sequences, comparison, logical testing, variable assignments, and custom data functions. 

The primary infix operators and their rank are listed below.  The rank of an operator indicates the order in which a function is processed by R.  This is relevant for dealing with complex expressions that involve two or more operators.  Rank also confirms if brackets or parenthesis are useful or redundant.  Examples in the table use the following data vectors as inputs:

List of Infix Operators in R

Operator	Rank	Type	Description	Comment
::	1	Extract	Function retrieval	Extract function from a package namespace. my.package::mean extracts a new mean function from my.package
:::	1	Extract	Function retrieval	Extract a hidden function from a namespace
$	2	Extract	List subset	Extract list data by name. See name() function
@	2	Extract	Slot selection	Extract attributes by memory slot or location. See slotnames() function
[ and [[	3	Extract	Subscripting	Extract data by index
^	4	Arithmetic	Exponential	2^3 = 8
:	5	Sequence	Sequence	1:3 = 1, 2, 3
%%	6	Arithmetic	Integer Divide	5 %/% 2 = 2 See floor function
%%	6	Arithmetic	Modulas	5 %% 2 = 1
%*%	6	Arithmetic	Matrix Multiplication	Multiplies two matrices that are conformable
%o%	6	Arithmetic	Outer Product	See help("%o%") for examples
%x%	6	Arithmetic	Kronecker product	See help("%x%") for examples
*	7	Arithmetic	Multiplication	Also matrix dot product
/	7	Arithmetic	Division	n/a
+	8	Arithmetic	Addition	n/a
-	8	Arithmetic	Subtraction	n/a
!	8	Comparison	Not	n/a
%in%	9	Comparison	Value Matching	value1 %in% value2: true false false
!=	9	Comparison	Not Equal To	value1 != value2: true true true
<	9	Comparison	Less Than	value1< 5: false true true
>	9	Comparison	Greater Than	value2 > 4: false true true
==	9	Comparison	Equal To	value2 == 5: false true false
<=	9	Comparison	Less Than Or Equal To	value1 <= value2: false true true
>=	9	Comparison	Greater Than Or Equal To	value1 >= value2: true false false
xor	10	Logical	Exclusive Or	xor(value1, value2): false, false, false
&	10	Logical	And (element)	value1==4 & value2 >=6: false false true > value1==4&value2 >=6 [1] false false true
&&	10	Logical	And (control)	is.na(value1[2]) && value2[1]==5: false
|	10	Logical	Or (element)	value1==7 | value2>=7: true false true
||	10	Logical	Or (control)	is.na(value1[1]) || value2[1]==4: false
~	11	Assignment	Equal	Used in formulas and model building
<<-	12	Assignment	Permanent Assignment	n/a
<-	13	Assignment	Left Assignment	n/a
->	13	Assignment	Right Assignment	n/a
=	13	Assignment	Argument Assignment	n/a

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