Arrays
Arrays are container-like values that can hold other values. The values inside an array are called elements.
| EXAMPLE |
|---|
| var breakfast = ["coffee", "croissant"]; breakfast; |
| OUTPUT |
| ["coffee", "croissant"] |
Array elements don’t all have to be the same type of value. Elements can be any kind of JavaScript value — even other arrays.
| EXAMPLE |
|---|
| var hodgepodge = [100, "paint", [200, "brush"], false]; hodgepodge; |
| OUTPUT |
| [100, "paint", [200, "brush"], false] |
Accessing Elements
To access one of the elements inside an array, you’ll need to use the brackets and a number like this: myArray[3]. JavaScript arrays begin at 0, so the first element will always be inside [0].
| EXAMPLE |
|---|
| var sisters = ["Tia", "Tamera"]; sisters[0]; |
| OUTPUT |
| "Tia" |
To get the last element, you can use brackets and `1` less than the array’s length property.
| EXAMPLE |
|---|
| var actors = ["Felicia", "Nathan", "Neil"]; actors[actors.length - 1]; |
| OUTPUT |
| "Neil" |
This also works for setting an element’s value.
| EXAMPLE |
|---|
| var colors = ["red", "yelo", "blue"]; colors[1] = "yellow"; colors; |
| OUTPUT |
| ["red", "yellow", "blue"] |
Properties and methods
Arrays have their own built-in variables and functions, also known as properties and methods. Here are some of the most common ones.
length
An array’s length property stores the number of elements inside the array.
| EXAMPLE |
|---|
| ["a", "b", "c", 1, 2, 3].length; |
| OUTPUT |
| 6 |
concat
An array’s concat method returns a new array that combines the values of two arrays.
| EXAMPLE |
|---|
| ["tortilla chips"].concat(["salsa", "queso", "guacamole"]); |
| OUTPUT |
| ["tortilla chips", "salsa", "queso", "guacamole"] |
pop
An array’s pop method removes the last element in the array and returns that element’s value.
| EXAMPLE |
|---|
| ["Jupiter", "Saturn", "Uranus", "Neptune", "Pluto"].pop(); |
| OUTPUT |
| "Pluto" |
push
An array’s push method adds an element to the array and returns the array’s length.
| EXAMPLE |
|---|
| ["John", "Kate"].push(8); |
| OUTPUT |
| 3 |
reverse
An array’s reverse method returns a copy of the array in opposite order.
| EXAMPLE |
|---|
| ["a", "b", "c"].reverse(); |
| OUTPUT |
| ["c", "b", "a"] |
