Arrays

Accessing items

We access items using their index, starting from 0.

js

const books = [
  'Things Fall Apart',
  'Beloved',
  'One Hundred Years of Solitude',
  'The God of Small Things',
  'Persepolis'
]

console.log(books[0])
console.log(books[3])

output

Things Fall Apart
The God of Small Things

Modifying items

We can assign new values to indices.

js

const books = [
  'Things Fall Apart',
  'Beloved',
  'One Hundred Years of Solitude',
  'The God of Small Things',
  'Persepolis'
]

books[2] = 'The Kite Runner'
console.log(books)

output

Things Fall Apart
Beloved
The Kite Runner
The God of Small Things
Persepolis

INFO

We used const books = , so why are we allowed to change the array? The books variable is the "container", but we're allowed to change what it contains. It is still the same array, just with different contents now.

Array .length

The .length property of an array returns the number of elements it contains.

js

const books = [
  'Things Fall Apart',
  'Beloved',
  'One Hundred Years of Solitude',
  'The God of Small Things',
  'Persepolis'
]

console.log(books.length)

output

5

This property is useful for accessing the last elements.

js

const books = [
  'Things Fall Apart',
  'Beloved',
  'One Hundred Years of Solitude',
  'The God of Small Things',
  'Persepolis'
]

console.log(books[books.length - 1])
console.log(books[books.length - 2])

output

Persepolis
The God of Small Things