In R, a matrix is a collection of elements of the same data type (boolean, numeric, or character) arranged into a fixed number of rows and columns.
matrix() function
Matrices can be created using the matrix() function. The matrix() function takes as input parameter a vector, followed by the nrow & ncol arguments to set the rows and columns of the formed matrix. Its return value is a 2d array, the matrix that was just formed.
Syntax
matrix(data, nrow, ncol)Parameters
It takes the following argument values:
data: It is the 1d vector we want to reshape in the form of a matrix.nrow: It is the number of rows of the matrix.ncol: It is the number of columns of the matrix.
Return Value
A matrix has rows equal to nrows and columns equal to ncols.
Remove rows and columns of a matrix
There can be more than one way to remove rows or columns from a matrix. But, the simplest one is using the concatenation c() function.
In order to remove the desired rows or columns from the matrix, we’ll use the minus (-) sign followed by the c() function. Inside the c() function we will pass the row and column numbers that we want to remove.
Example: Reshaping matrix in R
Matrix <- matrix(c(0, 1, 2, 3, 4, 5, 6, 7, 8), nrow = 3, ncol =3)
print(Matrix)
Matrix <- Matrix[-c(1), -c(1)]
print("After Removal the Matrix is: ")
print(Matrix)
- Line#1: Initializing a matrix having 3 rows & 3 columns.
- Line#2:Printing the matrix that we initialized in line 1.
- Line#4: Removing the first row and first column from the matrix using the
c()function by passing the desired row and numbers. - Line#6: Printing the matrix after the removal of the first row and column.
Output
