R Exercises | Programming Exercises for Finance in the R Language

Matrix Algebra: Exercises

1. Defining matrices. The function matrix(x, nrow, ncol) can be used to create a matrix object in R. The nrow and ncol parameters specify the number of rows and columns of the matrix. Additionally, x is a vector of values that is transformed into the matrix.

Start by defining a variable, vector, that consists of the integers from 1 to 20 using 1:20. Use matrix() to transform that variable into a 4x5 matrix.



                              # Define a vector of integers from 1 to 20.
                              vector <- c(___:___)

                              # Convert the vector into a 4x5 matrix.
                              matrix45 <- ___(___, nrow = 4, ncol = ___)

                              # Print the matrix.
                              print(matrix45)



                                # Define a vector of integers from 1 to 20.
                                vector <- c(1:20)

                                # Convert the vector into a 4x5 matrix.
                                matrix45 <- matrix(vector, nrow = 4, ncol = 5)

                                # Print the matrix.
                                print(matrix45)


                              test_error()
                              test_object("vector", incorrect_msg="Did you use `1:20` to define the vector of integers?")
                              test_object("matrix45", incorrect_msg="Did you use the `matrix()` function correctly?")
                              success_msg("Excellent work. Do you notice anything about the way the elements of the vector are ordered in the matrix?")

Check that you used the correct arguments for `matrix()`.

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