Regular Expressions 101

Sponsors

Community Patterns

1

Halacae Text

Created·2026-04-01 00:09
Flavor·PCRE2 (PHP)
Regular expression to match a valid line of text in Halacae, a constructed language by R74n.
Submitted by R74n
1

Halacae Word

Created·2026-04-01 00:08
Flavor·PCRE2 (PHP)
Regular expression to match valid words in Halacae, a conlang by R74n.
Submitted by R74n
1

R74n URLs

Created·2026-04-01 00:05
Flavor·PCRE2 (PHP)
Regular expression to match valid URLs on R74n websites.
Submitted by R74n
1

TA_P1

Created·2026-03-26 09:45
Flavor·PCRE2 (PHP)
Code
Submitted by anonymous
1

plfjahr42

Created·2026-03-25 07:21
Flavor·PCRE2 (PHP)
plf HIIILLFFEEE
Submitted by Lecksie Hartman
1

plfJahr4

Created·2026-03-25 07:14
Flavor·PCRE2 (PHP)
PLF hiilfe
Submitted by Lecksie Hartman
1

Murat67

Created·2026-03-24 22:53
Flavor·PCRE2 (PHP)
Isch des Tüff
Submitted by webler4000
1

wald493#2

Created·2026-03-24 20:24
Flavor·PCRE2 (PHP)
Wer den Löwen weckt muss auch mit ihm tanzen!
Submitted by Webler3000
1

Capture group finder

Created·2026-03-23 19:06
Flavor·PCRE2 (PHP)
A regex to inspect other regex and match all capture groups
Submitted by SP4CEBAR
1

translation batch name structure

Created·2026-03-16 13:15
Flavor·PCRE2 (PHP)
internal structure of a batch name
Submitted by msoutopico
2

Almost universal anime filename matcher

Created·2026-03-07 18:37
Flavor·Python
matches anime filenames. such as Group] Name [Episode[Audiometa]others.ext supports NCOP, NCED, OP, ED, SP, SPnn, nn, nn.n, nn.n_vn mp4, mkv, srt, ass but you could add more. the episode must be written within a [] bracket. finally, this regex cannot cover all the cases and obviously have some issues, but it's fine under most cases. it is also a small regex practice for me.
Submitted by NullCompute0754
2

GHAS Custom Secret Scanning Regex for Password/Secret/API Key (Excludes ${...} and process.env)

Created·2026-03-06 15:52
Flavor·PCRE2 (PHP)
This is a GitHub Advanced Security (GHAS) Secret Scanning Custom Pattern I created to detect likely hardcoded credentials while reducing common false positives in code. Goal: detect assignments for these key names: password secret apikey / api_key / api-key Pattern regex: (?i)\b(password|secret|api[-]?key)\b\s[:=]\s(?!\s\$\{)(?!\sprocess\.env\b)(?:['"])?[A-Za-z0-9!@#$%^&()+=-]{5,}(?:['"])? What it should catch (examples): password: "ahsjdfahsjfhdjsahj" secret = 'kjfskahfsdhfj' apikey: ABCDE12345!@# (unquoted) What it tries NOT to catch (common false positives): password: ${password_somename} (template/variable placeholder) secret: ${VAULT_SECRET} password: process.env.DB_PASSWORD (env var reference, not a hardcoded secret) This is intended as a practical baseline; it won’t be perfect for every language/config style. If you have suggestions to improve the detection accuracy (reduce false positives/false negatives) for GHAS custom patterns, please share.
Submitted by GearoidMaguire
1

Flatten 1 line CSS

Created·2026-03-01 16:22
Updated·2026-03-01 17:35
Flavor·PCRE2 (PHP)
Finds CSS selectors that only contain one line and, using the substitution, flattens everything to be on the same line.
Submitted by anonymous
1

IP address

Created·2026-03-01 02:22
Flavor·PCRE2 (PHP)
Matches and verifies IP address. 192.168.0.1 Matches 999.999.9.9 Didn't match
Submitted by anonymous
1

Validate an IP

Created·2026-02-25 11:06
Updated·2026-02-25 11:11
Flavor·PCRE2 (PHP)
52 character long regex to validate IP address.
Submitted by Karthik
1

number selector, with commas & decimals

Created·2026-02-12 05:04
Flavor·PCRE2 (PHP)
selects numbers, with commas and decimals, like 1,234.56
Submitted by Bicorn
1

Smart outer parentheses selector with backslash escaping

Created·2026-02-10 03:26
Updated·2026-02-12 01:11
Flavor·PCRE2 (PHP)
Grabs the outer parentheses and contents taking into account inner parentheses enclosures
Submitted by bicorn
1

nexus/sonartype composer cleanup of unfinished package versions

Created·2026-02-05 13:05
Flavor·PCRE2 (PHP)
matches composer packages with -alpha, -beta and -rc versionings
Submitted by Anna Damm
1

OmegaT Project Name (Pattern)

Created·2026-02-03 16:49
Flavor·PCRE2 (PHP)
Regex showing how to match the five parts in an OmegaT project name (named as per the internal convention at cApStAn), including labels for each captured group (each part in the name).
Submitted by msoutopico
1

unnecessary closing HTML tags

Created·2026-01-27 19:15
Flavor·PCRE2 (PHP)
Selects the ` and ` tags from a string. You can probably do this with something easier, but this works
Submitted by Twineee
1

Door_Double

Created·2026-01-27 07:54
Updated·2026-01-28 10:27
Flavor·Python
Regex for Door_Double
Submitted by anonymous
1

Laravel Log (MonoLog) Print

Created·2026-01-21 14:51
Updated·2026-01-21 15:00
Flavor·PCRE2 (PHP)
Extracts the following fields from a Laravel Log print: Time Stamp (Date) Log Level (supports optional prefix (ie. local.DEBUG)) Log Message Exception | Context If an exception is detected, the file reference (file path + line number), and optional stacktrace are captured.
Submitted by Jerren
1

Poland PESEL

Created·2026-01-21 11:23
Flavor·PCRE2 (PHP)
Correct Poland PESEL base regex validator. Covers birth dates up to 2099 year. PESEL numbers are in YYMMDDXXXXX format, however, the month is adjusted based on what year people were born. People born from 1900-1999 has no adjustment, 2000-2099 is the month +20, 2100-2199 is +40, 2200-2299 is +60. For example, if someone was born December 16, 2016, their PESEL would be 163216XXXXX.
Submitted by @Sldmk
1

PLF4 Formular mit Komponente

Created·2026-01-21 07:52
Flavor·PCRE2 (PHP)
PLF4
Submitted by anonymous
1

PLF3

Created·2026-01-21 07:38
Flavor·PCRE2 (PHP)
PLF3
Submitted by anonym
1

PLF2

Created·2026-01-21 07:22
Flavor·PCRE2 (PHP)
PLF2
Submitted by anonym
1

PLF1

Created·2026-01-21 07:20
Flavor·PCRE2 (PHP)
plf1
Submitted by anonym
1

Wasser

Created·2026-01-20 20:24
Flavor·PCRE2 (PHP)
hey das ist richtig coool oder?
Submitted by anonymous
1

Python -- Match container image reference parts

Created·2026-01-20 02:14
Updated·2026-01-20 02:28
Flavor·Python
This is a Python RE for matching different parts and combinations of various docker/container image references, as compatible with docker pull etc. Parts / Capture Groups image: # whole image repo: # everything but the tag/digest registry: # host+port host: port: name: # path within registry reference: # tag or digest (with : or @; I haven't bothered to figure out how to strip that yet) tag: digest: If it matches, it should match image, repo, and name at the very least.
Submitted by neal-ian
1

Match instagram URLs

Created·2026-01-13 23:29
Flavor·PCRE2 (PHP)
Matches instagram urls for posts, reels, and stories works on all flavors except rust
Submitted by User9684
1

Discord URL matching

Created·2026-01-13 23:19
Updated·2026-01-13 23:24
Flavor·PCRE2 (PHP)
match every type of discord url with each useful part in a group pretty optimized, shouldnt be too harsh on your system should work in every flavor except rust because rust sucks lol
Submitted by User9684
1

Match Bible References

Created·2026-01-12 14:12
Flavor·PCRE2 (PHP)
I've created this for a simple project of mine, it squishes every book of the Bible into a RegEx, with the full name, abbreviation, and abbreviation with a dot. Then, it matches the chapter and verse relatively simply.
Submitted by Twineee
1

Caculator seperator with groups

Created·2026-01-08 19:18
Flavor·PCRE2 (PHP)
Caculator seperator with groups
Submitted by CalcMan
1

HP Prime

Created·2025-12-30 04:20
Updated·2025-12-30 15:37
Flavor·PCRE2 (PHP)
Extracts HP Prime PPL numbers.
Submitted by anonymous
1

Strings

Created·2025-12-30 04:09
Updated·2025-12-30 04:11
Flavor·PCRE2 (PHP)
Extracting strings defined in languages like C/C++ etc.
Submitted by Insoft
1

1

Created·2025-12-28 04:09
Flavor·Python
554
Submitted by anonymous
1

U.S. Phone Number

Created·2025-12-23 19:40
Flavor·PCRE2 (PHP)
Format validation for U.S. phone numbers with or without a country code and with various formatting and punctuation permissible.
Submitted by Nick
1

AoC 2025 Day 5

Created·2025-12-19 23:04
Flavor·Python
AoC 2025 Day 5 part 1 but also works for part 2. You just don't need the IDs at the bottom for part 2
Submitted by anonymous
1

Telephone validation regex - handles international codes, extensions, and formatting gracefully

Created·2025-12-19 21:17
Flavor·PCRE2 (PHP)
Search string for use in contact cleaning project $1 = intenational code, omitting preceding "+" $2 = area code $3 = first three digits of phone number $4 = last four digits of phone $5 = extension, inclusive of any commas or hashes to automate phone tree navigation TO DO handle recursive menus (e.g., "321-321-1234,,,1234#,,123344#....)
Submitted by Jason
1

Changes Log Tag verify for Languages Code sub-versioning

Created·2025-12-18 10:41
Flavor·PCRE2 (PHP)
Search for the occurence of the 3 following words: CHA, LOG and TAG. Should be in the above order sequence (but it also if works swapped).
Submitted by XrosaXasorX
1

DoubleQuote Enclosed CSV Field with Escaped DoubleQuote

Created·2025-12-11 12:04
Flavor·PCRE2 (PHP)
Extract field value of DoubleQuote Enclosed CSV Field with Escaped DoubleQuote The matching field value still contains escaped double quotes to be later processed :-)
Submitted by Alper YAZGAN
1

test

Created·2025-12-09 04:53
Flavor·PCRE2 (PHP)
test
Submitted by anonymous
1

001

Created·2025-12-04 05:41
Flavor·PCRE2 (PHP)
for Problem 2 - Fancy Barcodes
Submitted by anonymous
1

Regex for MusicBrainz Picard Plugin – Title Cleaner OST

Created·2025-11-28 16:26
Updated·2025-11-28 16:26
Flavor·Python
One of the regular expressions I use for my plugin Title Cleaner OST.
Submitted by nrth3rnlb
1

souly2

Created·2025-11-26 11:03
Flavor·PCRE2 (PHP)
import React, { useState } from 'react'; // Example characters array as props for demonstration const charactersData = [ { name: 'Gandalf', isWizard: true }, { name: 'Harry', isWizard: true }, { name: 'Aragorn', isWizard: false } ]; // in der Component CharacterList function CharacterList({ characters }) { const [showOnlyWizards, setShowOnlyWizards] = useState(false); function handleFilterClick() { setShowOnlyWizards(!showOnlyWizards); } let visibleCharacters; if (showOnlyWizards) { visibleCharacters = characters.filter(function(character) { return character.isWizard === true; }); } else { visibleCharacters = characters; } return ( {showOnlyWizards ? 'Alle anzeigen' : 'Nur Zauberer anzeigen'} {visibleCharacters.map(function(character) { return {character.name}; })} ); } // in App.jsx export default function App() { return ; }
Submitted by anonymous
1

souly

Created·2025-11-26 10:52
Flavor·PCRE2 (PHP)
für julian <3
Submitted by anonymous
1

zweckfreibaum

Created·2025-11-26 07:04
Flavor·PCRE2 (PHP)
d
Submitted by anonymous
1

zweckfreibaum08

Created·2025-11-25 18:36
Flavor·PCRE2 (PHP)
08
Submitted by anonymous
1

Zwechfreibaum

Created·2025-11-25 18:23
Flavor·PCRE2 (PHP)
Leben
Submitted by anonymous
1

ReactMx

Created·2025-11-25 13:46
Flavor·PCRE2 (PHP)
laöhfdöädfh
Submitted by anonymous

Community Library Entry

1

Regular Expression
Created·2025-11-21 07:34
Flavor·PCRE2 (PHP)

/
matei
/
gm
Open regex in editor

Description

<?php session_start(); ?> <!DOCTYPE html> <html> <head> <title>Produktverwaltung</title> </head> <body> <?php class Produkt { private $name; private $preis; private $id; public function __construct($name = '', $preis = 0) { $this->setName($name); $this->setPreis($preis); $this->id = uniqid(); } public function setName($name) { $this->name = $name; } public function getName() { return $this->name; } public function setPreis($preis) { $this->preis = $preis; } public function getPreis() { return $this->preis; } public function getId() { return $this->id; } } if (isset($_POST['speichern'])) { $neuesProdukt = new Produkt($_POST['name'], $_POST['preis']); if (!isset($_SESSION['produkte'])) { $_SESSION['produkte'] = array(); } $_SESSION['produkte'][$neuesProdukt->getId()] = $neuesProdukt; } if (isset($_POST['loeschen'])) { unset($_SESSION['produkte']); $_SESSION['produkte'] = array(); } ?> <form method="POST"> <label>Produktname:</label> <input type="text" name="name" value="Beispielprodukt" required><br><br> 
<label>Preis:</label>
<input type="number" name="preis" value="10.99" step="0.01" min="0" required><br><br>

<button type="submit" name="speichern" value="speichern">Speichern</button>
<button type="submit" name="loeschen" value="loeschen">Alle löschen</button>
</form> <h3>Gespeicherte Produkte:</h3> <?php if (isset($_SESSION['produkte'])) { foreach ($_SESSION['produkte'] as $produkt) { echo "<p>Produkt: " . $produkt->getName() . "</p>"; } } ?> </body> </html>
Submitted by anonymous