Creating Matrices in R
Matrices can be created and analyzed in a few different ways in R.
One way is to create the matrix yourself. There are a few different ways you can do this.
The matrix(a, nrow = b, ncol = c)
command in R creates a matrix that repeats the element a
in a matrix with b
rows and c
columns.
A matrix can be manually created by using the c()
command as well.
This exercise is part of the course
Linear Algebra for Data Science in R
Exercise instructions
The command
matrix(1, nrow = 2, ncol = 3)
creates a 2 by 3 matrix of1
's. Create a 3 by 2 matrix of2
's and print the result.The command
matrix(c(1, 2, 3, 2), nrow = 2, ncol = 2, byrow = FALSE)
creates a 2 by 2 matrix by superimposing the vectorsc(1,2)
andc(3,2)
as columns. Changebyrow
to equal TRUE and print the result.A 2 by 2 matrix of
1
's (calledA
) is provided for you. Add this matrix to the previous matrix using the+
command.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Create two matrices of all 1's and all 2's that are 2 by 3 and 3 by 2, respectively
matrix(1, nrow = 2, ncol = 3)
print(matrix(___, nrow = 3, ncol = ___))
# Create a matrix B and change the byrow designation.
B <- matrix(c(1, 2, 3, 2), nrow = 2, ncol = 2, byrow = FALSE)
B <- matrix(c(1, 2, 3, 2), nrow = 2, ncol = 2, byrow = ___)
# Add A to the previously-created matrix B
A + ___