JavaScript Arrays
An array is a special JavaScript object used to store multiple values in a single variable. Arrays allow storing values of different data types and provide built-in methods for efficient data manipulation.
What you'll cover
Learning objectives
- Understand JavaScript Arrays
- Create arrays using literals
- Create arrays using constructors
- Access array elements
- Understand array length
- Iterate arrays
- Create 2D arrays
- Store mixed data types
Prerequisites
Related topics
Concept breakdown
What is an Array?
An array stores multiple values in a single variable.
Array Index
Array indexing starts from 0.
Array Literal
The preferred way to create arrays.
Array Constructor
Arrays can also be created using new Array().
Two Dimensional Arrays
Arrays can contain other arrays.
JavaScript Arrays
> "[10,20,30,"Sathesh",null,true,40]"> "object"> "7"> "10"> "20"> "30"> "Sathesh"> "null"> "true"> "40"> "[[10,20,30],[40,50,60],[70,80,90]]"> "[10,20]"> "3x3 empty array"
Step by step
- 1
Create Array
Create using literal.
- 2
Display
Print the array.
- 3
Length
Use length property.
- 4
Loop
Iterate using for loop.
- 5
2D Array
Create nested arrays.
- 6
Constructor
Create using Array constructor.
Key takeaways
Key points
- Zero-based indexing
- Dynamic size
- Mixed data types supported
- Literal notation preferred
- Supports multidimensional arrays
Advantages
- Easy
- Dynamic
- Fast access
- Mixed types
- Built-in methods
Disadvantages
- Mixed types reduce readability
- Large arrays use memory
Student Marks
Store student marks in an array.
Frequently asked questions
A collection of values stored in one variable.
0
Literal and Constructor.
Yes.
Total elements.
Yes.
Array Literal.
array[0].
length-1
Built-in JavaScript Array object.
Quick MCQ practice
1. Index starts from?
2. Preferred creation?
3. Property for size?
4. 2D array contains?
5. Array literal uses?
Practice on your own
Coding exercise
Employee Array
Create and display an employee array.
Assignment
- Create an array
- Display using loop
- Create 2D array
- Use constructor
- Print length
Tags
References
