Python Regex Tester โ re Module ยท findall ยท match ยท sub Code
Real-time ยท 26 features ยท AI explain ยท Unit tests ยท Diff mode ยท JS/Python/PHP ยท 100% browser
Test Python regular expressions with re module compatibility. Get re.findall, re.match, re.sub, re.IGNORECASE, re.MULTILINE, and re.DOTALL code snippets. Warnings shown for Python-specific syntax differences.
What is a Regular Expression?
A regular expression (regex) is a sequence of characters that defines a search pattern. Used for validation, parsing, text manipulation, and data extraction in virtually every programming language โ JavaScript, Python, PHP, Java, and more.
How to Use This Regex Tester
Type your regex pattern in the input field. Matches highlight in real-time in the test text panel. Use the flags (g/i/m/s/u/y) to modify matching behavior. Switch between Test, Replace, Unit Test, Diff, and Multi-string modes using the tabs above.
Frequently Asked Questions
How is Python regex different from JavaScript?
Python uses r"..." raw strings to avoid double escaping. Flags are re.IGNORECASE, re.MULTILINE, re.DOTALL instead of single characters. Python's re module lookbehind requires fixed-width patterns.
What is the difference between re.match() and re.search()?
re.match() only matches at the BEGINNING of the string. re.search() searches the entire string. Use re.search() when you don't know where the match will be.
How do I get all matches in Python?
re.findall(pattern, text) returns a list of all matching strings. re.finditer(pattern, text) returns an iterator of match objects with position info, groups, etc.
What is the re.DOTALL flag in Python?
re.DOTALL makes . match any character including newline โ equivalent to the /s flag in JavaScript. Without it, . does not match \n.
How do named groups work in Python?
Use (?P<name>...) syntax in Python (different from JS). Access with match.group("name") or match.groupdict(). In re.sub, use \g<name> for named group backreferences.