In this article, we will study the various available data types in R and where they are used. Data types form the basic building blocks of any programming language. R is a dynamically typed language. Therefore, there is no need to make an explicit declaration of the data type of the variable. Each variable is associated with a data type on the basis of which memory allocation is done. For instance, the integer data type occupies 2 bytes and the character variable occupies 1 byte, respectively.
Types of data types in R
R contains a large number of data types, some of which are namely:
Logical data types in R
The logical data types in R are basically the boolean type R objects. There is assigned a boolean TRUE or FALSE value. The TRUE value can also be defined using the T value and FALSE using F respectively. Logical data types can also be assigned as a result of the condition evaluation.
#declaring logical data type variables #assigning True boolean value to var1 var1 = TRUE #assigning False boolean value to var2 var2 = F
Numeric data types in R
All sets of real numbers fall under the category of numeric data types. These may be decimals or whole numbers. The default data type for the numerical variables is numeric.
#declaring numeric data type variables #example1 var1 = 3.42 #example2 var2 = 1/2 #example3 var3 = -5 #example 4 var4 = 9 #example5 var5 = 1e-3 class(var5)
Integer data types in R
Integer data types are a subset of the numeric data type, which is inclusive only of numbers without decimal points. This implies that only integers are included in this category. Most such numbers are appended with the letter ‘L’. It may include negative or positive numbers.
#declaring integer data type variables #example1 var1 = 456L #example2 var2 = -3L #example3 var3 = 1/2L
Integer data types can also be declared using the method as.integer(num) which can convert any numeric data type to an integer.
#declaring integer data type variables #example1 var1 = 456L #example2 var2 = -3L #example3 var3 = 1/2L
Complex number in R
A complex number in mathematical form comprises a real number and an imaginary counterpart. In R, any variable is implicitly cast to the type of complex number if it is appended with the letter ‘i’.
#declaring complex number data type variables #example1 var1 = i #example2 var2 = 2-2i
String data type in R
The string or character data types comprise the letters, numbers, or special characters. Any value enclosed within a single or double quotation mark is considered to belong to the string data type. It may contain dates as well.
#declaring string variables var1 = "FoxInfoTech" var2 = '@' var3 = "1970-03-12"
Examining data types in R
There are a large number of functions in-built in R in order to understand the particular data type associated with any R object.
class() method
The class() method is used to validate the data type associated with any variable. This method takes as a parameter the variable to be checked. It is the high-level denotion of the object.
#declaring examples
var1 = i
var2 = 43
var3 = as.integer(var2)
var4 = "FoxInfoTech"
var5 = T
var6 = 1e-3
var7 = '%'
#checking the data type
cat("var1 : ",class(var1))
cat("var2 : ",class(var2))
cat("var3 : ",class(var3))
cat("var4 : ",class(var4))
cat("var5 : ",class(var5))
cat("var6 : ",class(var6))
cat("var7 : ",class(var7))
The code produces the following output :
var1 : integer var2 : numeric var3 : integer var4 : character var5 : logical var6 : numeric var7 : character
typeof() method
The typeof() method also depicts which category the particular data type falls into. It is the low-level denotion of the object. For instance, the numeric data type is implicitly stored in the form of “double” value with two decimal points in it, that is, 5 is stored as 5.00 in R.
#declaring examples
var1 = i
var2 = 43
var3 = as.integer(var2)
var4 = "FoxInfoTech"
var5 = T
var6 = 1e-3
var7 = '%'
cat("var1 : ",typeof(var1))
cat("var2 : ",typeof(var2))
cat("var3 : ",typeof(var3))
cat("var4 : ",typeof(var4))
cat("var5 : ",typeof(var5))
cat("var6 : ",typeof(var6))
cat("var7 : ",typeof(var7))
The code produces the following output :
var1 : integer var2 : double var3 : integer var4 : character var5 : logica var6 : double var7 : character
as.data_type() method
This method is used to simulate the conversion of a variable from one data type to another in R. The data_type that is specified in this method is the corresponding data type to which the value is mapped.
#conversion of data type
var1= 5
cat("Initial var1 : ", class(var1))
#conversion to string
var2 = as.character(5)
cat("Final var2 : ", class(var2))The output produced is as follows :
Initial var1 : numeric Final var2 : character
Similarly, methods like as.logical or as.complex can also be used to carry out successive conversions.
