regex101: build, test, and debug regex
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.
RegEX Cheat Sheet & Quick Reference
Lookaround lets you match a group before (lookbehind) or after (lookahead) your main pattern without including it in the result.
Java Code Conventions: must match pattern '^[a-z][a-zA-Z0-9]*$'
Oct 30, 2012 · ^ means start-of-string, [a-z] means a character between a and z inclusive matched 1 time (= 1 lower case letter), [a-zA-Z0-9]* means 'zero or more characters in [a-zA …
Regular expression syntax cheat sheet - JavaScript | MDN
Jul 8, 2025 · Non-word character class escape: Matches any character that is not a word character from the basic Latin alphabet. Equivalent to [^A-Za-z0-9_]. For example, /\W/ or /[^A …
Regex Tutorial - How to write Regular Expressions?
Apr 12, 2024 · Write your pattern using the special characters and literal characters. Use the appropriate function or method to search for the pattern in a string. To match a sequence of …
Regex Cheat Sheet - A Regular Expressions Guide - HackerNoon
Oct 2, 2024 · A phone number regex pattern must include country code but does not have to extract that part even though it must match on string. [] matches specified single character, …
Frequently Used Regex Patterns - TutorialsTeacher.com
Regex expressions are used frequently in searching or validating different formats. The followings are frequently used regex patterns. Regex pattern ^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+.[A-Za …
Regex Cheat Sheet
Jan 5, 2025 · These verbs can optimize performance, enforce logic, or debug complex patterns by altering how the engine handles matches and failures. Below is a brief introduction to each …
Easy to follow Regular Expression Cheatsheet - DEV Community
Dec 8, 2024 · I prepared this Regular expression cheatsheet with the help of various resources. I hope this helps. (...) (?:...) (?=...) (?!...) (?<=...) (?<!...) `^ [A-Za-z0-9._%+-]+@ [A-Za-z0-9.-]+. …
regex101: ^[a-zA-Z0-9\\._-]+@[a-zA-Z0-9-]{2,}[.][a-zA-Z]{2,4}$
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.