A Beginner's Guide to Regular Expressions — Learn Regex in 10 Minutes

What Are Regular Expressions?

A regular expression (regex) is a pattern that matches combinations of characters in a string. It is an extraordinarily powerful tool for searching text, validating input, and extracting data.

Basic Patterns

Literal Characters

The simplest regex is a plain string: hello matches the text "hello" anywhere in a larger string.

Special Characters (Metacharacters)

Character	Meaning	Example
.	Any single character	h.t matches "hat", "hot", "hit"
^	Start of string	^Hello matches "Hello World"
$	End of string	world$ matches "hello world"
\d	One digit	\d{3} matches "123"
\w	Letter, digit, or underscore	\w+ matches "hello"
\s	Whitespace character	\s+ matches spaces and tabs

Quantifiers

Quantifier	Meaning
*	0 or more times
+	1 or more times
?	0 or 1 time
{n}	Exactly n times
{n,m}	Between n and m times

Practical Examples

Email Validation

[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}

US Phone Number

\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}

URL Pattern

https?://[\w.-]+\.[a-zA-Z]{2,}[/\w.-]*

Try It Yourself

Practice is the best teacher. Test your regular expressions with real-time match highlighting in the free Regex Tester.