## What is an R Array?

a) A multi-dimensional data structure that stores elements of the same type

b) A single-dimensional vector

c) A list of matrices

d) A method for importing data into R

### Answer:

a) A multi-dimensional data structure that stores elements of the same type

### Explanation:

An array in R is a multi-dimensional data structure that stores elements of the same type. Arrays can have more than two dimensions, making them a generalization of matrices. They are useful for handling data that requires more than two dimensions, such as 3D data or time series data.

```
# Creating a 3-dimensional array
my_array <- array(1:12, dim = c(2, 3, 2))
# Printing the array
print(my_array)
# Output:
# , , 1
# [,1] [,2] [,3]
# [1,] 1 3 5
# [2,] 2 4 6
#
# , , 2
# [,1] [,2] [,3]
# [1,] 7 9 11
# [2,] 8 10 12
```

In this example, a 3-dimensional array named `my_array`

is created with dimensions 2x3x2, filled with numbers 1 to 12. The array has two 2×3 matrices stacked on top of each other.

Arrays are powerful for managing complex datasets in R, particularly when working with data that naturally fits into multiple dimensions.