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.
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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.