JavaScript Object : RegExp Object
- Regular Expression is best way for pattern matching.
- Regular Expression Object is pattern of the character that we are going to match with String provided by user.
- Regular Expression is used to match pattern and to perform “search and replace” function.
Syntax : RegExp Object in JavaScript
var str = new RegExp(pattern,modifiers);
- pattern will specify the pattern of the expression.
- modifier will tell whether the search is
- Case-sensitive
- Global
- Multi-line.
| Modifier | Description |
|---|
| i | This Modifier is used to perform Case Insensitive Search Operation |
|---|
| g | This Modifier is used to perform Global Match |
|---|
| m | This Modifier is used to perform Multiline Matching |
|---|
Brackets : Find a range of characters
| Expression | Description |
|---|
| [abc] | Find any character between the brackets |
| [^abc] | Find any character not between the brackets |
| [0-9] | Find any digit from 0 to 9 |
| [A-Z] | Find any character from uppercase A to uppercase Z |
| [a-z] | Find any character from lowercase a to lowercase z |
| [A-z] | Find any character from uppercase A to lowercase z |
| [adgk] | Find any character in the given set |
| [^adgk] | Find any character outside the given set |
| (red|blue|green) | Find any of the alternatives specified |
Metacharacters : Characters with a special meaning
| Metacharacter | Description |
|---|
| . | Find a single character, except newline or line terminator |
| w | Find a word character |
| W | Find a non-word character |
| d | Find a digit |
| D | Find a non-digit character |
| s | Find a whitespace character |
| S | Find a non-whitespace character |
| b | Find a match at the beginning/end of a word |
| B | Find a match not at the beginning/end of a word |
| Find a NUL character |
| n | Find a new line character |
| f | Find a form feed character |
| r | Find a carriage return character |
| t | Find a tab character |
| v | Find a vertical tab character |
| xxx | Find the character specified by an octal number xxx |
| xdd | Find the character specified by a hexadecimal number dd |
| uxxxx | Find the Unicode character specified by a hexadecimal number xxxx |
RegExp Object Properties
| Property | Description |
|---|
| global | Specifies if the “g” modifier is set |
| ignoreCase | Specifies if the “i” modifier is set |
| lastIndex | The index at which to start the next match |
| multiline | Specifies if the “m” modifier is set |
| source | The text of the RegExp pattern |
RegExp Object Methods
| Method | Description |
|---|
| compile() | Compiles a regular expression |
| exec() | Tests for a match in a string. Returns the first match |
| test() | Tests for a match in a string. Returns true or false |