R Data Types
R has a wide variety of data types. Here, we will mention some of the most frequently used data types. These are the most frequently used data types -
- Vectors
- Lists
- Matrices
- Arrays
- Factors
- Data Frames
Vectors
A vector represents a set of elements of the same mode, which can be integer, floating number, character, complex and so on. A vector is a basic data object in R. In R, a single number is also considered as one element vector instead of calling a scalar vector. The concatenation function c, is used to create a vector. It binds the element together of the same type.
Example of vectors
The example below contains some numeric elements in a vector.
num <- c(10, 3, 4, 5, 6)
print(num)
[1] 10 3 4 5 6
The example below contains all string type elements in a vector.
animales <- c("dog", "cat", "elephant", "fox")
print(animales)
[1] "dog" "cat" "elephant" "fox"
We can also write a logical vector in which the values are either True and False. In R, TRUE and FALSE can also be abbreviated to T and F.
logical <- c(T, T, F, T)
Lists
R provides list() function to create lists which may contain different objects. We can also say that it can combine objects of different types. A list is a generic vector. A vector has all elements of the same type, but a list may contain elements of different types.
Example of Lists
The example below contains student's data in a list and access the data by using the print function.
l1 <- list(c(5, 3, 5), c('sophiya', 'somya', 'Jorz'), 'IT', age=12)
print(l1)
[[1]]
[1] 5 3 5
[[2]]
[1] "sophiya" "somya" "Jorz"
[[3]]
[1] "IT"
$age
[1] 12
Matrices
A matrix (plural: matrices) is a rectangular array of numbers, symbols, or expressions, arranged in rows and columns. It has two-dimensional structures. All columns in a matrix are the same type and of the same length. In R, a matrix is created by using the matrix() function. The number of rows and columns of the matrix is assigned in nrow and ncol.
Example of Matrices
The example below creates a matrix of two rows and two columns.
y <- matrix(c(1,2,3,4),nrow=2,ncol=2)
print(y)
[,1] [,2]
[1,] 1 3
[2,] 2 4
Arrays
In R, the array() function is used to create data objects which can store more than two dimensions.
Example of Array
x <- array(1:12, dim=c(2,2,3))
print(x)
, , 1
[,1] [,2]
[1,] 1 3
[2,] 2 4
, , 2
[,1] [,2]
[1,] 5 7
[2,] 6 8
, , 3
[,1] [,2]
[1,] 9 11
[2,] 10 12
Factors
Factors are a special variable type for storing categorical variables. A factor can contain both integers and strings and it is generally used in statistical modeling. The factor() function is used to create a factor.
Example of Factors
The example below contains a factor of working days.
f <- c("Mon", "Tues", "Wed", "Thu", "Fri")
fdata <- factor(f)
print(fdata)
[1] Mon Tues Wed Thu Fri
Levels: Fri Mon Thu Tues Wed
Data Frames
A Data Frame is a list of vectors of equal length. It has two dimensional array like structure, in which the elements should be same in each column.
Example of Data Frames
The example below contains a data frame of students.
data <- data.frame(id = c(1:4), name = c("Mary", "Soy", "Alexa", "Roxy"), class = 5)
print(data)
id name class
1 1 Mary 5
2 2 Soy 5
3 3 Alexa 5
4 4 Roxy 5