Data Types

Let's begin with discussing the basic data types in R, declaring variables and more.

We'll cover the following

Basic Data Types in R

Everything in R is an object.

R is a language designed to store, manipulate, and work with Data. Thus, it makes sense to make all utilities of R an object that stores data.

In every computer language, variables are used for accessing data stored in memory. R does not provide direct access to the computer’s memory but rather provides several specialized data structures referred to as objects. These objects can be symbols, variables, functions, etc.

Variables in R

Variables are used to store data. Their value can be changed, used and manipulated according to need. A unique name given to a variable (function or object as well) is called an identifier.

Important points while writing Identifiers in R: Identifiers can have a combination of letters, digits, one period . and one underscore _. However, they must start with a letter or a period. If it starts with a period, it cannot be followed by a digit. Reserved words in R cannot be used as identifiers!

Reserved words are keywords that have special meaning and functions, for example, pi is a reserved word. It has a value of 3.141..3.141... As we move ahead in the course we will encounter many reserved words and learn their functions.

To declare a variable, we need to assign a variable an identifier.

To add value to the variable, we can use <-, = or ->.

Syntax for declaring variables in R

# declaring a variable using `<-`
nameOfVariable <- value

# declaring a variable using `=`
nameOfVariable = value

# declaring a variable using `->`
value -> nameOfVariable

Main Data Types

To make the best of the R language, we need a strong understanding of the basic data types in R. R has five main data types.

widget

In the following code, we declare the different types of variables and use class() to determine what kind of object it is. This is called the high-level data type of an object.

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# Variables of different types
# Using `<-` operator
# Real Numeric
myRealNumeric <- 10
class(myRealNumeric)
# Decimal Numeric
myDecimalNumeric <- 10.0
class(myDecimalNumeric)
# Using `=` operator
# Character
myCharacter = "10"
class(myCharacter)
# Logical
myBoolean = TRUE
class(myBoolean)
# Using `->` operator
# Integer
0:10 -> myInteger 
class(myInteger)
#Complex
5i -> myComplex
class(myComplex)

To determine the data type of the object at the low level we can use typeof(). Another method that we’d like to introduce here is length() that returns the length of the data in the variable.

A method refers to code that performs a specific task and is associated to an object.

In the code snippet below, we print the type and length of the variable myInteger:

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# Testing typeof() and length()
myInteger <- 1:10
cat("The type of the variable is", typeof(myInteger), "\n") # returns low level data type
cat("The length of the variable is", length(myInteger), "\n") # returns length of variable

In R language, if you change the data in a variable, i.e., overwrite any previous information stored in an object, then the previous information will be deleted. So remember not to use names that are already taken.

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myInteger <- 1:10
cat("myInteger: ")
cat(myInteger, "\n")
myInteger <- 11:20 # Overwriting myInteger
cat("myInteger: ")
cat(myInteger, "\n")