Arrays: Arrays of arrays

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Since we can add an array into an array, we can create multi-dimensional arrays, which have very useful applications (e.g. a matrix):

const matrix = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
]

matrix[0][0] //1
matrix[2][0] //7

Lessons in this unit:

0: Introduction
1: Number of items in an array
2: Create a new array from an existing array
3: Adding an item to an existing array
4: Adding at the beginning of an array
5: Adding multiple items to the array
6: Removing an item from an array
7: Modifying an existing array without mutating it
8: ▶︎ Arrays of arrays
9: Filling an array
10: Array destructuring
11: Check if an array contains a specific value
12: Array Recipes