# Array exercises

**R-exercises**, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)

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**Exercise 1**

Create an array (3 dimensional) of 24 elements using the `dim()`

function.

**Exercise 2**

Create an array (3 dimensional) of 24 elements using the `array()`

function.

**Exercise 3**

Assign some dimnames of your choice to the array using the `dimnames()`

function.

**Exercise 4**

Assign some dimnames of your choice to the array using the arguments of the `array()`

function.

**Exercise 5**

Instead of column-major array, make a row-major array (transpose).

**Exercise 6**

For this exercise, and all that follow, download this file, and read it into R using the `read.csv()`

function, e.g.:

```
temp
Copy the column named N
```

into a new variable `arr`

.

**Exercise 7**

Set dimensions of this variable and convert it into a 3 * 2 * 4 array. Add dimnames.

**Exercise 8**

Print the whole array on the screen.

**Exercise 9**

Print only elements of height 2, assuming the first dimension represents rows, the second columns and the third heigth.

**Exercise 10**

Print elements of height 1 and columns 3 and 1.

**Exercise 11**

Print element of height 2, column 4 and row 2.

**Exercise 12**

Repeat the exercises 9-11, but instead of using numbers to reference row, column and height, use `dimnames`

.

Image: Cubo completato” by Masakazu “Matto” Matsumoto from Nagoya, Japan – http://flickr.com/photos/vitroids/1527092739/. Licensed under CC BY 2.0 via Wikimedia Commons.

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