Matrices in R Programming - The Ultimate Guide

What are Matrices?

Matrices are the R objects wherein the elements are organized in a 2-D rectangular shape. In a matrix, it contains elements of the same atomic types.

The matrix function is denoted as a matrix().

Syntax

matrix(data, nrow, ncol, byrow, dimnames)

• data is the parameter of input,
• nrow is number of rows and
• ncol is the number of columns to be created;
• byrow has TRUE or FALSE as its logical values, and dimname is the rows or columns name.
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Accessing Elements of a matrix

Any row or column element can be accessed by using the column and row index.

Example:

#Defining the column and row names
rn = c("r1", "r2", "r3", r4")
cn = c("c1", "c2", "c3")
#Creating the matrix
A <- matrix(c(1:12), nrow = 4, byrow = TRUE, dimnames= list(rn, cn))
#Accessing 2nd row, 3rd column element
print(A[2,3])
#Accessing  elements of 4th column
print(A[ ,4])

Output:

[1] 6 
row1  row2  row3  row4
   3        6          9        12

Matrix Computations

Different types of mathematical operations such as matrix addition, subtraction, multiplication, and division can be performed on the matrices using R Programming operators.

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