R Variables

A variable is a memory allocated for the storage of specific data and the name associated with the variable is used to work around this reserved block. The name given to a variable is known as its variable name. Usually a single variable stores only the data belonging to a certain data type. The name is so given to them because when the program executes there is subject to change hence it varies from time to time.

Variables in R

R Programming Language is a dynamically typed language, i.e. the R Language Variables are not declared with a data type rather they take the data type of the R-object assigned to them. This feature is also shown in languages like Python and PHP.

Declaring and Initializing Variables in R Language

R supports three ways of variable assignment:

Using equal operator- operators use an arrow or an equal sign to assign values to variables.
Using the leftward operator- data is copied from right to left.
Using the rightward operator- data is copied from left to right.

R Variables Syntax

Types of Variable Creation in R:

Using equal to operators
variable_name = value

using leftward operator
variable_name <- value

using rightward operator
value -> variable_name

example:

# R program to illustrate

# Initialization of variables

# using equal to operator

var1 = "hello"

print(var1)

# using leftward operator

var2 <- "hello"

print(var2)

# using rightward operator

"hello" -> var3

print(var3)

output

[1] "hello"

[1] "hello"

[1] "hello"

Nomenclature of R Variables

The following rules need to be kept in mind while naming a R variable:

 

• A valid variable name consists of a combination of alphabets, numbers, dot(.), and underscore(_) characters. Example: var.1_ is valid
• Apart from the dot and underscore operators, no other special character is allowed. Example: var$1 or var#1 both are invalid
• Variables can start with alphabets or dot characters. Example: .var or var is valid
• The variable should not start with numbers or underscore. Example: 2var or _var is invalid.
• If a variable starts with a dot the next thing after the dot cannot be a number. Example: .3var is invalid

Important Methods for R Variables

R provides some useful methods to perform operations on variables. These methods are used to determine the data type of the variable, finding a variable, deleting a variable, etc. Following are some of the methods used to work on variables:

class() function

This built-in function is used to determine the data type of the variable provided to it. The R variable to be checked is passed to this as an argument and it prints the data type in return.

Syntax

    class(variable)

Example:

var1 = "hello"

print(class(var1))

output:

[1] "character"

ls() function

This built-in function is used to know all the present variables in the workspace. This is generally helpful when dealing with a large number of variables at once and helps prevents overwriting any of them.

Syntax 

     ls()

Example:

# using equal to operator

var1 = "hello"

# using leftward operator

var2 <- "hello"

# using rightward operator

"hello" -> var3

print(ls())

output:

[1] "var1" "var2" "var3"

rm() function

This is again a built-in function used to delete an unwanted variable within your workspace. This helps clear the memory space allocated to certain variables that are not in use thereby creating more space for others. The name of the variable to be deleted is passed as an argument to it.

Syntax 

     rm(variable)

Example:

# using equal to operator

var1 = "hello"

# using leftward operator

var2 <- "hello"

# using rightward operator

"hello" -> var3

# Removing variable

rm(var3)

print(var3)

output

ERROR!

Error in print(var3) : object 'var3' not found

Execution halted