An array is a special kind of variable that lets you store a list of values together. Instead of a single wire that connects a name to one value, imagine an array as a long wire with many slots—each holding a single value. These slots are called 

For example, consider the following array:

In this code we declare a variable fruits using 

and assign it an array of three string values. Each value is stored at a specific index:

To create an array, you use square brackets with a comma-separated list of values:

You can also create an empty array and add values later:

You can access an element by using its index. For example, to get the first element of the fruits array, you write:

The number inside the square brackets tells JavaScript which item you want to read.

You can change the value at any index. For example, if you want to change "banana" to "blueberry" in the fruits array:

This “reconnects” the wire at index 1 to a new value.

 method lets you add a new value to the end of an array. Imagine that your array is a long wire with several connection points, and push() attaches a new connection at the end.

 method removes the last element from an array. It “disconnects” the final connection point from the wire and returns the removed value.

Assign it an array containing the strings "red", "green", and "blue".

Print the entire array using console.log(colors).

index.js

index.test.js

Creating and Printing an Array

Assign it an array with the values [5, 10, 15].

Print the updated element using console.log(numbers[1]).

Accessing and Updating an Array Element

Assign "cat" to index 0, "dog" to index 1, and "bird" to index 2.

Print the entire array using console.log(animals).

Creating an Empty Array and Filling It

Assign it an array containing the strings "red" and "green".

Use the push() method to add "blue" to the array.

Print the updated array using console.log(colors).

Adding an Element with push()

Assign it an array containing [1, 2, 3, 4].

Use the pop() method to remove the last element and store it in a variable called removed.

Print both the updated array and the removed element using console.log.

Removing an Element with pop()

### What Is an Array?

An array is a special kind of variable that lets you store a list of values together. Instead of a single wire that connects a name to one value, imagine an array as a long wire with many slots—each holding a single value. These slots are called **indices**, and they are numbered starting at 0.

For example, consider the following array:

```javascript
let fruits = ["apple", "banana", "cherry"];
```

In this code we declare a variable fruits using **let **and assign it an array of three string values. Each value is stored at a specific index:

- "apple" is at index 0
- "banana" is at index 1
- "cherry" is at index 2

@embed 95bfd91fc199

## Creating an Array

To create an array, you use square brackets with a comma-separated list of values:

```javascript
let numbers = [1, 2, 3, 4];
```

You can also create an empty array and add values later:

```javascript
let emptyArray = [];
emptyArray[0] = "first";
emptyArray[1] = "second";
```

---

## Accessing Array Elements

You can access an element by using its index. For example, to get the first element of the fruits array, you write:

```javascript
console.log(fruits[0]); // prints "apple"
```

The number inside the square brackets tells JavaScript which item you want to read.

```javascript
fruits[1] = "blueberry";
console.log(fruits); // prints ["apple", "blueberry", "cherry"]
```

---

## Updating Array Elements

You can change the value at any index. For example, if you want to change "banana" to "blueberry" in the fruits array:

```javascript
fruits[1] = "blueberry";
console.log(fruits); // prints ["apple", "blueberry", "cherry"]
```

This “reconnects” the wire at index 1 to a new value.

---

## Adding Elements with push()

The **push()** method lets you add a new value to the end of an array. Imagine that your array is a long wire with several connection points, and push() attaches a new connection at the end.

For example:

```javascript
let colors = ["red", "green"];
colors.push("blue");
console.log(colors); // prints ["red", "green", "blue"]
```

---

## Removing Elements with pop()

The **pop()** method removes the last element from an array. It “disconnects” the final connection point from the wire and returns the removed value.

For example:

```javascript
let numbers = [1, 2, 3, 4];
let removed = numbers.pop();
console.log(numbers); // prints [1, 2, 3]
console.log(removed); // prints 4
```

### Exercises

@exercise ca3245921f6f

@exercise cbdc0777b190

@exercise 508a46dc071b

@exercise 72cee1630a0d

@exercise db59fd4ac6bd


- Luo muuttuja nimeltä **colors** käyttäen **let**-avainsanaa.
- Anna sille arvoksi taulukko, joka sisältää merkkijonot "punainen", "vihreä" ja "sininen".
- Tulosta koko taulukko käyttäen console.log(colors).

Taulukon luominen ja tulostaminen

- Luo muuttuja nimeltään numbers käyttäen **let**-avainsanaa.
- Aseta sille arvoksi taulukko arvoilla \[5, 10, 15\].
- Päivitä indeksissä 1 oleva alkio arvoon 20.
- Tulosta päivitetty alkio (**numbers\[1\]**) käyttäen **console.log()**-funktiota.

Taulukon elementin hakeminen ja päivittäminen

- Luo muuttuja nimeltä animals käyttäen **let**-avainsanaa.
- Alusta se tyhjään taulukkoon.
- Anna arvot "kissa" indeksille 0, "koira" indeksille 1 ja "lintu" indeksille 2.
- Tulosta koko taulukko käyttäen console.log(animals).

Tyhjän taulukon luominen ja täyttäminen

- Luo muuttuja nimeltään colors käyttäen **let**-avainsanaa.
- Määritä sille taulukko, joka sisältää merkkijonot "punainen" ja "vihreä".
- Käytä push() -metodia lisätäksesi "sininen" taulukkoon.
- Tulosta päivitetty taulukko käyttäen console.log(colors).

Elementin lisääminen push()-funktiolla

- Luo muuttuja nimeltä **numbers** käyttäen **let**.
- Anna sille arvoksi taulukko joka sisältää \[1, 2, 3, 4\].
- Käytä pop() -metodia poistaaksesi viimeisen elementin ja tallentaaksesi sen muuttujaan nimeltä **removed**.
- Tulosta päivitetty taulukko ja poistettu elementti käyttäen console.log.

Elementin poistaminen pop()-funktiolla

Arrays - Storing Multiple Values

Learn programming with JavaScript, arguably the most important and versatile programming language in today's world, at least for web development.

Welcome to Hakatemia’s beginner-friendly JavaScript course, where you will learn the fundamentals of programming with JavaScript. In today’s world, JavaScript is one of the most popular and versatile programming languages—especially in web development, where it holds a unique position: no other programming language can run both in the browser and on the server. For this reason, JavaScript has become extremely popular and is used for developing user interfaces (React, Vue, Angular, Svelte, etc.), back-end systems (NodeJS/Express, HAPI, etc.), and full-stack solutions (NextJS, NuxtJS, etc.).

These JavaScript frameworks will be covered in later Hakatemia courses, but before we get there, we must first master the basics of JavaScript programming. This course is designed precisely for that purpose.

Throughout the course, you’ll learn core programming concepts such as variables, operators, conditional statements, functions, arrays, and objects. Each module is divided into small, manageable segments with plenty of practical exercises.

This course is being released as a beta—the first part of Hakatemia’s comprehensive web development curriculum—and it is the first course that uses Hakatemia’s new programming exercise environment. Please provide feedback using the button at the bottom of the page or on Discord if you encounter any issues!

Arrays - Storing Multiple Values

What Is an Array?

Creating an Array

Learn to hack — start here