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JavaScript•Working with Data

RegExp Character Classes

Character Classes are characters enclosed in square brackets []. A character class matches any character from a set within brackets:

// Match Digits const pattern = /[0-9]/;

JavaScript Regex Character Classes

Revised July 2025

Class

Description

[a]

Matches the character between the brackets

[^a]

Matches all characters NOT between the brackets

[abc]

Matches all characters between the brackets

[^abc]

Matches all characters NOT between the brackets

Formula

[a - z]

Matches all characters in the range from a to z

Formula

[^a - z]

Matches all characters NOT in the range from a to z

Formula

[0 - 9]

Matches all characters in the range from 0 to 9

Formula

[^0 - 9]

Matches all characters NOT in the range from 0 to 9

Example [HW]

A global search for the characters "H" and "W" in a string:
let text = "Hello World!";
const pattern = /[HW]/g;
let result = text.match(pattern);

Example [A-Z]

A global search for the upper case characters "A" to "Z" in a string:
let text = "This is W3School";
const pattern = /[A-Z]/g;
let result = text.match(pattern);

Example [1234]

A global search for the characters "1", "2", "3" and "4" in a string:
let text = "123456789";
const pattern = /[1234]/g;
let result = text.match(pattern);

Example [1-4]

A global search for the characters "1" to "4" in a string:
let text = "123456789";
const pattern = /[1-4]/g;
let result = text.match(pattern);

Formula

[01234] is the same as [0 - 4]
[abcde] is the same as [a - e]

Regular Expression Methods

Regular Expression

Search and

Replace can be done with different methods.

These are the most common:

String Methods

Method

Description match(

regex )

Returns an Array of results matchAll(

regex )

Returns an Iterator of results replace(

regex )

Returns a new String replaceAll(

regex )

Returns a new String search(

regex ) Returns the index of the first match split( regex )

Returns an Array of results

RegExp Methods

Method

Description regex.exec() Returns an Iterator of results regex.test()

Returns true or false

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