Matrices are the R objects wherein the elements are organized in a 2-D rectangular shape. In a matrix it contains elements of same atomic types.
Matrix function is denoted as matrix().
matrix(data, nrow, ncol, byrow, dimnames)
data is the parameter of input, nrow is number of rows and ncol is number of columns to be created; byrow has TRUE or FALSE as its logical values, and dimname is the rows or columns name.
Accessing Elements of a matrix
Any row or column element can be accessed by using column and row index.
#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
#Accessing elements of 4th column
row1 row2 row3 row4
3 6 9 12
Different types of mathematical operations such as matrix addition, subtraction, multiplication and division can be performed on the matrices using R operators.