R- Variables

Variables in R Programming

R Variables Definition

Variables are defined as identifier or named space in the memory, which are stored and can be referenced and also can be manipulated later in the program. R language is a Dynamically Typed and also Interpreted language where Type Checking of the variable and other objects is commited at the run time.

R Rules of Variables

Rule 1: The variable name has to start with letter and can contain letter, number, underscore (“_”) or period (“.”).

Example:

“varName1”, “my.variable” are valid variable names
“2var” is not a valid variable name

Rule 2: Underscore (“_”) at the beginning of the variable name is not allowed.

Example:

“_myvariable” is not a valid variable

Rule 3: Period (“.”) at the beginning of the variable name is allowed but must not be followed by numbers. It is recommended in R to use period (“.”) to separate the different words for the identifier.

Example:

“.varone” is a valid variable
“.1var” is not a valid variable

Rule 4: Special characters such as “&”, “#”, etc., along with white space (space, tabs) are not allowed in a variable name.

Example:

“var$2”, “var#2” are not valid variables

Rule 5: Reserved words or keywords are not allowed as a variable name.

Example:

“TRUE”, “FALSE” are not valid variables

Variable Assignment

Three ways of variable assignment in R.

“=” Operator: “=” used to assign the value.
Example : my.variable = 100

“<-” Operator: The value on the right is assigned to the left variable.
Example: my.variable <- 123

“->” Operator: The value on the left is assigned to the right variable.
Example: 999 -> my.variable

How To Determine Variable

Variable in R can be determined by function class(), typeof() and mode().

‘class()’ – will give the high-level type of an object. It is used to determine the data type of the variable provided to it.

Example:

varx <- "hello"
print(class(varx))

#Output:
[1] "character"

‘typeof()’ – will return values which matches the internal type of object in R. It is mostly used by R programmer to determine the type of an object.

Example:

typeof(2) 
typeof(2.8) 
typeof("3") 
typeof("gfg") 
typeof(1 + 2i) 

#output:
[1] "double"
[1] "double"
[1] "character"
[1] "character"
[1] "complex"

‘mode()’ – will returns the values which are the same and closely related to ‘typeof().’

Example:

mode(7) 
mode(2.7) 
mode("9") 
mode("xyz") 
mode(4 + 6i) 

#output:
[1] "numeric"
[1] "numeric"
[1] "character"
[1] "character"
[1] "complex"

How to Show All Presented Variables

“ls()” function is used to show all the present variables in the workspace.

Example:

var1<- "hello"
print(ls())

#output:
[1] "var1"

How to Remove Variables

‘rm()’ function is used to remove or delete variable in R.

Example:

var2<- "hello"
rm(var2)
print(var2)

#output:
Error: object 'var2' not found

Congratulations

Congratulations, you have finished this tutorial of R variables.