Course Content

# R Introduction: Part II

R Introduction: Part II

## matrix() Function

Sometimes you may have only one vector that you need to convert into a matrix. How can it be done? The answer is simple - by using the `matrix()`

function.

This function has the following parameters:

These are not all the parameters, but the most important for us.

`data`

- is the vector that we want to use to build the matrix.`nrow`

- number of rows in a new matrix.`ncol`

- number of columns in a new matrix.`byrow`

- logical, should the matrix be filled by rows. It's important to note that the length of the vector filled as the`data`

parameter must be divisible by`nrow`

or`ncol`

. If both parameters are set, then`nrow*ncol`

must equal the vector length. For example, let's construct a 3x3 matrix with integers from 1 to 9.

As you can see, this matrix was built from above to below first. Let's set parameter `byrow`

to `T`

and compare the results.

As you can see, we filled this matrix from left to right. We were free to leave only one of the `nrow`

or `ncol`

parameters since 9 (number of elements in the vector) is divisible by 3 and returns an integer result.

# Task

Given a vector of numbers named `num`

.

Based on this vector, you need to build the following matrix.

Use only the `matrix()`

function, and think about the correct values of parameters.

How does `seq()`

function work? `seq(a, b)`

generates integers from `a`

to `b`

inclusive. `seq(a, b, c)`

generates integers from `a`

to `b`

with the step `c`

.

Everything was clear?