[Arrays]

Learning Objectives

create an array
choose an element
change or replace an element
add and remove elements
find the size of an array
loop through an array

Definition

An array is a collection of items in an ordered list

Arrays in JavaScript are represented using square brackets

[ ]

   ['one', 2, true]

Each item in an array is called an element and is specified using an index

index	value
0	'one'
1	2
2	true

Indexes begin with a 0

let arr = ['one', 2, true]

Dynamic

Unlike other lower level languages, arrays in JavaScript are dynamic.

This means we can add to and remove from arrays as we choose.

let arr = ['one', 2, true]

Arrays can also contain a mixture of data types

There are several ways to create a new array

// creates a new instance of an array
let arr1 = new Array(); 

//creates a new array with four elements
let arr2 = new Array(4); 
 
//creates an array with four elements and their values
let arr3 = new Array(2,'three', 'four', 5); 

//most common ways to create an array
let arr4 = []; 

let arr5 = [2, 'three', 'four', 5];

# PRESENTING CODE

Array Creation

There are many methods we can use on arrays including:

- push()

- shift()

- unshift()

- length()

- sort()

- reverse()

You can learn about other array methods at:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

{code}

Let's take a look at some Code!