Array

The array is the most useful data structure.

Note
A data structure is a specialized format for organizing and working with data collection. An array is a collection of items where each item is a value.

Creating an Array

To create an array, use square brackets []:

This creates an empty array with no elements. To create an array with elements, place the elements inside [] and separate them with commas (,):

Note
The last element in the array should not have a comma after it.

To print an array, simply use console.log():

Indexes

Each element in an array has a unique index.

Note
Indexes start from 0. The first element has an index of 0, the second element has an index of 1, and so on.

Accessing array data is done by specifying the index in square brackets ([index]) after the array name:

Arrays can hold different data types, including number, string, boolean, and more.

Length Property

The length property is a built-in property of arrays that represents the number of elements in that array. To use this property, use the following syntax:

1. Which brackets are used to create an array?

2. Retrieve the second element from the array:

3. How do you get the length of the array?

Which brackets are used to create an array?

Select the correct answer

( )

{ }

[ ]

Retrieve the second element from the array:

Select the correct answer

arr[1]

arr[2]

arr[3]

arr[0]

How do you get the length of the array?

Select the correct answer

arr.len

arr.len()

arr.length

arr.length()

Everything was clear?

Section 2. Chapter 6

Course Content

Introduction to JavaScript

1. Basic Concepts

About JavaScript Syntax Challenge: Console Output Comments Challenge: Single-line Comment Challenge: Multi-line Comment

2. Variables and Data Types

Variables Challenge: Defining the Variable const Data Types Overview null Array Array Methods Challenge: Array Operations

3. Basic Operations

Assignment Mathematical Operations Operations with Assignment Increment and Decrement Challenge: Variable Operations Comparison Operations Logical Operations Challenge: Comparing Variables String Concatenation Challenge: Sentence Building

4. Conditional Statements

if else else if Challenge: Determining Size

5. Loops

while do while Challenge: Printing Numbers from 5 to 9 for Challenge: Tigers break continue Challenge: Stopping and Skipping

6. Functions

What is a Function?Definition Challenge: My Name Arguments return Challenge: Sum Summary

Array

The array is the most useful data structure.

Note
A data structure is a specialized format for organizing and working with data collection. An array is a collection of items where each item is a value.

Creating an Array

To create an array, use square brackets []:

This creates an empty array with no elements. To create an array with elements, place the elements inside [] and separate them with commas (,):

Note
The last element in the array should not have a comma after it.

To print an array, simply use console.log():

Indexes

Each element in an array has a unique index.

Note
Indexes start from 0. The first element has an index of 0, the second element has an index of 1, and so on.

Accessing array data is done by specifying the index in square brackets ([index]) after the array name:

Arrays can hold different data types, including number, string, boolean, and more.

Length Property

The length property is a built-in property of arrays that represents the number of elements in that array. To use this property, use the following syntax:

1. Which brackets are used to create an array?

2. Retrieve the second element from the array:

3. How do you get the length of the array?

Which brackets are used to create an array?

Select the correct answer

( )

{ }

[ ]

Retrieve the second element from the array:

Select the correct answer

arr[1]

arr[2]

arr[3]

arr[0]

How do you get the length of the array?

Select the correct answer

arr.len

arr.len()

arr.length

arr.length()

Everything was clear?

Section 2. Chapter 6