Regular Expression
S
A passionate Full Stack Software Developer 🚀 having an experience of building Web applications with JavaScript and some other cool libraries and frameworks.
A regular expression is a sequence of characters that forms a search pattern. When you search for data in a text, you can use this search pattern to describe what you are searching for. A regular expression can be a single character or a more complicated pattern.
Regular Expression Modifiers
Modifiers can be used to perform case-insensitive more global searches:
| Modifier | Description |
| i | Perform case-insensitive matching |
| g | Perform a global match (find all matches rather than stopping after the first match) |
| m | Perform multiline matching |
Regular Expression Patterns
Brackets are used to find a range of characters:
| Expression | Description | |
| [abc] | Find any of the characters between the brackets | |
| [0-9] | Find any of the digits between the brackets | |
| (x | y) | Find any of the alternatives separated with |
Metacharacters are characters with a special meaning:
| Metacharacter | Description |
| \d | Find a digit |
| \s | Find a whitespace character |
| \b | Find a match at the beginning of a word like this: \bWORD, or at the end of a word like this: WORD\b |
| \uxxxx | Find the Unicode character specified by the hexadecimal number xxxx |
Quantifiers define quantities:
| Quantifier | Description |
| n+ | Matches any string that contains at least one n |
| n* | Matches any string that contains zero or more occurrences of n |
| n? | Matches any string that contains zero or one occurrences of n |
