JS ObjectsLesson #92
RegExp Character Classes
Character Classes are characters enclosed in square brackets [].
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]/;
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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 |
| [a-z] | Matches all characters in the range from a to z |
| [^a-z] | Matches all characters NOT in the range from a to z |
| [0-9] | Matches all characters in the range from 0 to 9 |
| [^0-9] | Matches all characters NOT in the range from 0 to 9 |
Example [HW]
Example Code
javascriptlet text = "Hello World!";
const pattern = /[HW]/g;
let result = text.match(pattern);Example [A-Z]
Example Code
javascriptlet text = "This is W3School";
const pattern = /[A-Z]/g;
let result = text.match(pattern);Example [1234]
Example Code
javascriptlet text = "123456789";
const pattern = /[1234]/g;
let result = text.match(pattern);Example [1-4]
Example Code
javascriptlet text = "123456789";
const pattern = /[1-4]/g;
let result = text.match(pattern);[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 |
See Also:
> JavaScript RegExp Tutorial
> JavaScript RegExp Flags
> JavaScript RegExp Meta Characters
> JavaScript RegExp Assertions
> JavaScript RegExp Groups
> JavaScript RegExp Quantifiers
> JavaScript RegExp Patterns
> JavaScript RegExp Objects
> JavaScript RegExp Methods
Interactive Code Examples
Example [HW]
javascriptJavaScript syntax and algorithm demonstration.
let text = "Hello World!";
const pattern = /[HW]/g;
let result = text.match(pattern);Example [A-Z]
javascriptJavaScript syntax and algorithm demonstration.
let text = "This is W3School";
const pattern = /[A-Z]/g;
let result = text.match(pattern);Example [1234]
javascriptJavaScript syntax and algorithm demonstration.
let text = "123456789";
const pattern = /[1234]/g;
let result = text.match(pattern);Example [1-4]
javascriptJavaScript syntax and algorithm demonstration.
let text = "123456789";
const pattern = /[1-4]/g;
let result = text.match(pattern);