Exercise

# Change the data frame to a matrix

One of the parts of the code that `profvis`

highlighted was the line where we generated the possible dice rolls and stored the results in a data frame:

```
df <- data.frame(d1 = sample(1:6, 3, replace = TRUE),
d2 = sample(1:6, 3, replace = TRUE))
```

We can optimize this code by making two improvements:

- Switching from a data frame to a matrix
- Generating the 6 dice rolls in a single step

This gives

```
m <- matrix(sample(1:6, 6, replace = TRUE), ncol = 2)
```

Instructions

**100 XP**

- Read and understand the data frame solution
`d()`

. - Complete the matrix solution,
`m()`

.`m()`

should create a`matrix`

with 6 elements and 2 columns.

- Use the
`microbenchmark()`

function to compare the timings of`d()`

and`m()`

.