Regular Expressions 101

Sponsors

Community Patterns

42

Cron schedule

Created·2016-06-02 15:45
Flavor·PCRE (Legacy)
Recommended·
Validate cron lines (even the ones commented out)
Submitted by anonymous
34

Parsing browser User Agents

Created·2015-01-23 16:47
Updated·2023-07-19 08:36
Flavor·PCRE (Legacy)
From a (fairly large) list of User Agent strings, extract the OS, Browser, and Device Type.
Submitted by OnlineCop
21

Get path from any text

Created·2023-01-31 14:38
Updated·2023-07-23 20:17
Flavor·PCRE2 (PHP)
Recommended·
Get path (windows style) from any type of text (error message, e-mail corps ...), quoted or not. THIS IS THE SINGLE LINE VERSION ! If you want understand how it work or edit it, go https://regex101.com/r/7o2fyy Relative path are not supported The goal is to catch what "Look like" a path. See the limitations UNC path and prefix path like //./], [//?/] or [//./UNC/] are allowed some url path like [file:///C:/] or [file://] are allowed Catch path quoted with ["] and [']. But these quotes are include with the catch Quoted path is not concerned by limitations Limitations : (only unquoted path) [dot] and [space] is allowed, but not in a row [dot+space] or [space+dot at end of file name isn't catched INSIDE A NAME FILE (or last directory if it is a path to a directory) : [comma] is not supported (it stop the catch) after a first [dot], any [space] stop the catch after a [space], catch is stoped if next character is not a [letter], [digit] or [-] so, double [space] stop the catch Compatibility compatible PCRE, PCRE2 AutoHotkey : don't forget to escape "%" in "`%" /!\ Powershell and .Net /!\\ : this regex need some modification to be interpreted by powershell. You have to replace each (?&CapturGroupName) by \k. Use this powershell code to do this replacement : ` $powershellRegex = @' [Put here the regex to replace (?&CapturGroupName) with \k] '@ -replace '\(\?&(\w+)\)', '\k' ` This example code must return : [Put here the regex to replace \k with \k]
Submitted by nitrateag
37

Strict Password Validator

Created·2018-01-31 01:03
Updated·2023-07-19 15:28
Flavor·JavaScript
This regex matches only when all the following are true: password must contain 1 number (0-9) password must contain 1 uppercase letters password must contain 1 lowercase letters password must contain 1 non-alpha numeric number password is 8-16 characters with no space
Submitted by qho
13

Conventional Commits validation

Created·2022-01-03 20:30
Updated·2022-04-05 20:20
Flavor·Python
This regex prevents the writing of non-standard conventional commits. I'm available on my github
Submitted by Krisque
15

RFC3339 DateTime

Created·2016-02-12 11:44
Flavor·PCRE (Legacy)
Recommended·
Validates a RFC3339 DateTime format. Does not validates the Data
Submitted by anonymous
16

CSS Color Matcher

Created·2023-08-07 02:36
Flavor·JavaScript
Pattern matching and extracting color code formats using RegEx. https://github.com/Kyza/color-regex/
Submitted by Kyza
10

IP Address (with 0s)

Created·2015-09-28 21:24
Flavor·JavaScript
Matches all valid IP addresses from 0.0.0.0 to 255.255.255.255
Submitted by Ryan Plummer
12

Find Reddit Threads

Created·2015-03-12 09:23
Flavor·Python
Simply searches for the thread-id in any kind of valid reddit-URL.
Submitted by Mio
15

Email regex validation

Created·2019-03-17 21:49
Updated·2023-07-27 21:03
Flavor·JavaScript
RegEx email /^((?!\.)[\w-_.]*)(@\w+)(\.\w+(\.\w+)?)$/gim; Just playing with Reg Ex. This to validate emails in following ways The email couldn't start or finish with a dot The email shouldn't contain spaces into the string The email shouldn't contain special chars ( mailname@domain.com First group takes the first string with the name of email \$1 => (mailname) Second group takes the @ plus the domain: \$2 => (@domain) Third group takes the last part after the domain : \$3 => (.com)
Submitted by https://www.linkedin.com/in/peralta-steve-atileon/
11

extract subdomain(if available) or domain from URL

Created·2016-04-08 13:05
Flavor·Python
This regex should extract the subdomain, if any, or the domain, if no subdomain is used, from an arbitrary URL
Submitted by trevi@twanda.com
6

Find and extract email domain

Created·2016-04-03 17:03
Flavor·Python
Find and extract email domain. Ex: test@example.pt -> extract 'example.pt'
Submitted by Fnxk
6

Quartz Cron Validation

Created·2015-07-27 12:13
Flavor·PCRE (Legacy)
http://stackoverflow.com/questions/2362985/verifying-a-cron-expression-is-valid-in-java
Submitted by anonymous
16

us postal/zip

Created·2014-01-13 22:15
Flavor·JavaScript
no description available
Submitted by jay johnson
24

grab valid css rules and properties

Created·2015-06-03 19:17
Flavor·JavaScript
no description available
Submitted by Pavel Dominguez
10

entity

Created·2015-11-20 01:12
Flavor·Python
no description available
Submitted by anonymous
83

Distinguish torrent files (series vs movies)

Created·2014-06-26 09:59
Updated·2023-07-20 15:08
Flavor·Python
A neat regex for finding out whether a given torrent name is a series or a movie. Returns the full name of the series with the separator needed to make it pretty (ie, replace it with space or what you want). Also returns the season number or the year for the movie/series, depending on what was previously matched.
Submitted by Firas Dib
13

US Currency Format

Created·2016-01-23 17:46
Flavor·JavaScript
no description available
Submitted by anonymous
9

Fixo LDN CSP e SEM CSP

Created·2014-11-18 14:02
Flavor·PCRE (Legacy)
no description available
Submitted by Marcos Müller
485

regex101.com permalink id grabber

Created·2013-12-12 13:09
Updated·2024-04-11 14:32
Flavor·PCRE (Legacy)
Grabs the ID for the regex101.com permalink code. If a revision number is provided, grab that as well.
Submitted by chris mccoy
238

Matching email addresses per RFC5322

Created·2013-10-23 17:46
Flavor·PCRE (Legacy)
The BNF rules from RFC 5322 transformed to PCRE by Nikita Popov and described in the post http://nikic.github.io/2012/06/15/The-true-power-of-regular-expressions.html.
Submitted by Michael Musson
10

money: either 0 or 2 dp

Created·2015-11-18 19:34
Flavor·JavaScript
no description available
Submitted by anonymous
10

MikroTik FireWall

Created·2015-05-30 10:27
Flavor·PCRE (Legacy)
Regex used in Splunk to extract fields from Mikrotik FW. NOTES: Mikrotik must be configured to use "BSD Syslog" format FW rules must add, as log prefix, the action: drop accep reject etc...
Submitted by HappyIdeasMaker
11

remove comments from php code

Created·2015-05-26 15:18
Flavor·PCRE (Legacy)
no description available
Submitted by anonymous
13

Match Gmail Email

Created·2014-11-20 23:58
Flavor·PCRE (Legacy)
Recommended·
Match Gmail Email
Submitted by Óscar Enríquez
13

Credit Card Expiry Date

Created·2015-05-26 05:34
Flavor·JavaScript
Allows inserting expiry date as MM/YYYY or MM-YYYY format
Submitted by Rider
5

Regex for Validating Egyptian Mobile Numbers with Specific Operator Codes

Created·2024-12-18 19:51
Flavor·PCRE2 (PHP)
This regular expression is designed to validate Egyptian mobile phone numbers by ensuring they conform to the following format: Country Code: The number must start with +20, representing Egypt's international dialing code. Mobile Networks: (Vodafone: 10, e&:11, Orange:12, we:15) Operator Code: The phone number must be followed by one of the valid operator prefixes (10, 11, 12, or 15), corresponding to major mobile networks in Egypt. Number Length: The phone number must have exactly 8 digits following the operator code, for a total of 11 digits (including the country code and operator code). This regex is commonly used to ensure that the input phone numbers follow the standard Egyptian format and belong to the correct mobile operators.
Submitted by Mohamed Amir
5

C# Regex Extract/Match Nested HTML Elements/Tags

Created·2022-03-03 19:13
Updated·2023-08-01 07:26
Flavor·.NET 7.0 (C#)
With this C# regex, you can easily match/Parse Nested HTML tags. Example input: someTitle SomeHeader anotherHeader HelloWorld Output: anotherHeader HelloWorld string pattern = $@"{ startP }((?'nested'{ openP })|{ closeP }(?'-nested')|\w\W]?){ closeP }"; *'StartP' (Must include open tag), example: <div id="target" *'openP' example: <div *'closeP' example: </div References: [In Depth with RegEx Matching Nested Constructions In Depth with .NET RegEx Balanced Grouping Regular expression matches closed HTML tags (nesting is supported)
Submitted by w4po
5

Email

Created·2021-07-10 13:06
Flavor·PCRE2 (PHP)
email format control
Submitted by ahmetbarut
5

among us references

Created·2021-05-03 17:10
Updated·2021-05-07 18:00
Flavor·JavaScript
it detects among us references among us aming us mongus amogus sus suspect was not the impostor no imposters remain 3 impostors remain
Submitted by h
5

get specific value from html tag

Created·2016-09-25 06:08
Flavor·PCRE (Legacy)
no description available
Submitted by A.ROA
5

Match Only Text

Created·2016-07-05 03:56
Flavor·Python
no description available
Submitted by anonymous
5

psswd

Created·2016-03-24 09:04
Flavor·Python
no description available
Submitted by anonymous
5

Form Tag

Created·2016-02-26 06:49
Flavor·Python
Form Tag
Submitted by Jay Patel
5

look for any $_POST['name']

Created·2016-01-14 23:35
Flavor·PCRE (Legacy)
if you are as lazy as me and want to replace every "=$_POST['name'];" using Dreamweaver or any development tool that allows using regular expressions to search in current file/document.
Submitted by Kevinator
5

import url image

Created·2015-12-18 08:44
Flavor·Python
import url image
Submitted by bartimeys
5

Validate hex color

Created·2015-12-02 11:14
Flavor·PCRE (Legacy)
Validates hexadecimal color codes based on the following rule set: Optionally starting with a hash. 3 or 6 characters in length. Using the [0-9a-f] character set.
Submitted by Nathaniel Blackburn
5

Codice fiscale italiano

Created·2015-10-09 09:14
Flavor·PCRE (Legacy)
Oltre a supportare le omocodie controlla in modo restrittivo il carattere relativo al mese di nascita
Submitted by Aldo Medri
5

Variable name of code

Created·2015-09-19 11:18
Flavor·PCRE (Legacy)
To get a variable name from a source code: The variable name is before the '=' (equal sign) This is the way to detect. Problem: Only 1 variable can get from 1 line. Unfortunately, this can get variable between after "//" and before ";" too. I made this for fake script debugger. Just get variable from source code and put that after last semicolon with so much tab and messagebox code for every line.
Submitted by Setsuna
5

relative to absolute

Created·2015-01-20 01:16
Flavor·PCRE (Legacy)
relative to absolute
Submitted by xp_prg
7

Remove Widows (PHP)

Created·2015-09-13 13:44
Flavor·PCRE (Legacy)
Adds a non-breaking space between the last two words of sentences
Submitted by herkulano
7

Extract currency with currency symbol if present

Created·2015-09-11 11:35
Flavor·JavaScript
Extracts values of the form £nnn,nnn.nn or $nnn.nnn from text
Submitted by Simon Gardner
7

simple email

Created·2015-06-11 01:12
Flavor·JavaScript
no description available
Submitted by anonymous
7

IOS3166 Country Code Identification REGEX

Created·2015-06-07 04:48
Flavor·Python
IOS3166 Country Code Identification REGEX
Submitted by theitgeek@recu.org.uk
7

validate US (5 & 9 digit) ZipCodes and CA PostalCodes

Created·2015-05-15 18:00
Flavor·PCRE (Legacy)
no description available
Submitted by anonymous
7

TimezoneOffset

Created·2014-12-09 07:00
Flavor·JavaScript
used to parse timezone in the format -08:00 or +05:30
Submitted by Neha
7

[A-Za-z\x{0600}-\x{06FF}\x{1000}-\x{1021}_-][-\w]*

Created·2014-11-03 16:04
Flavor·PCRE (Legacy)
A-Za-z\x{0600}-\x{06FF}\x{1000}-\x{1021}_-*
Submitted by [A-Za-z\x{0600}-\x{06FF}\x{1000}-\x{1021}_-][-\w]*
7

SO: fail2ban regular to find 403 request in nginx

Created·2014-09-15 11:32
Updated·2023-07-27 20:59
Flavor·Python
http://stackoverflow.com/q/25778420/2072035
Submitted by anonymous
73

Regex for telephone numbers all over the world

Created·2014-04-08 07:58
Updated·2023-10-09 14:47
Flavor·JavaScript
Recommended·
Detects most of the phone numbers all over the world
Submitted by Aditya Joshi
4

semver

Created·2014-10-03 18:53
Flavor·PCRE (Legacy)
Recommended·
Semantic Versioning regex pattern according to Tom Preston-Werner http://semver.org/ https://github.com/mojombo/semver/blob/master/semver.md First version of this regex follows semver 2.0.0. Discussion of semver and this regex was posted on https://github.com/mojombo/semver.org/issues/59
Submitted by @gvlx <Gerardo Lisboa>

Community Library Entry

1

Regular Expression
Created·2023-05-14 05:03
Flavor·JavaScript

/
^(?!-00:00)(?=^(?:Z|[\+\-](?:0[0-9]|1[012]):00|\+0[34569]:30|\+10:30|-03:30|-09:30|\+13:00|\+14:00|\+05:45|\+08:45|\+12:45))^((Z)|([\+\-])(\d\d):(\d\d))$
/
gm
Open regex in editor

Description

Time Zone UTC Offsets in actual use for ISO 8601 / RFC 3339 Date Times (Museum of Bad Data)

https://regex101.com/library/F21Glr

Matches only (and every) UTC offset that is in actual use and valid under ISO 8601 and RFC 3339 (Y'know, the '2008-08-08T08:08:08+05:00' looking one, this is the plus/minus sign part and what follows, or the 'Z' for UTC).

This regex will work in all versions of Javascript past and present. The Expanded version with the comments will not.

Edge cases:

  • Rejects -00:00, which is valid RFC 3339 but invalid ISO 8601.
  • Accepts 13:00, 14:00, -03:30, and other yes-those-are-valid offsets

References:

Test cases:


// Time Zone UTC Offsets in actual use for ISO 8601 / RFC 3339 (Museum of Bad Data)
// Accept: UTC indicator
Z
// Accept: Valid +xx:00
+00:00
+01:00
+02:00
+03:00
+04:00
+05:00
+06:00
+07:00
+08:00
+09:00
+10:00
+11:00
+12:00
+13:00
+14:00
// Accept: Valid -xx:00
-01:00
-02:00
-03:00
-04:00
-05:00
-06:00
-07:00
-08:00
-09:00
-10:00
-11:00
-12:00

// Accept: Valid +xx:30
+03:30
+04:30
+05:30
+06:30
+09:30
+10:30

// Accept: Valid +xx:45
+05:45
+08:45
+12:45

// Accept: Valid -xx:30
-03:30
-09:30

// Accept: Valid: 30 offsets

+03:30
+04:30
+05:30
+06:30
+09:30
+10:30
-03:30
-09:30

// Accept: Valid :45 offsets
+05:45
+08:45
+12:45

// Reject: valid RFC 3339, invalid ISO 8601

-00:00

// Reject: no such UTC offset in use
-13:00
-14:00
+00:01
+00:03
+00:99
+20:00
+0:00
// Reject: no such UTC offset in use

+01:30
+07:30
+08:30
+02:30
+11:30
+12:30
+13:30
+14:30
-01:30
-02:30
-04:30
-05:30
-06:30
-07:30
-08:30
-10:30
-11:30
-12:30
-13:30
-14:30

// Reject: Unused :45 offsets
+01:45
+02:45
+03:45
+04:45
+06:45
+07:45
+09:45
+10:45
+11:45
+13:45
+14:45
-01:45
-02:45
-03:45
-04:45
-05:45
-06:45
-07:45
-08:45
-09:45
-10:45
-11:45
-12:45
-13:45
-14:45

+01:15
+02:15
+03:15
+04:15
+05:15
+06:15
+07:15
+08:15
+09:15
+10:15
+11:15
+12:15
+13:15
+14:15
-01:15
-02:15
-03:15
-04:15
-05:15
-06:15
-07:15
-08:15
-09:15
-10:15
-11:15
-12:15
-13:15
-14:15

// Reject: Z stands alone
Z00:00
Z00
Z0
// Reject: hyphen required
0100
+0100
-0100
// Reject: colon required
+0100
// Reject: No extra characters
2001-02-03T04:05:06.007+0800
+08:00 
 +08:00

Expanded Pattern:

^(?!-00:00)(?=^(?:Z|[\+\-](?:0[0-9]|1[012]):00|\+0[34569]:30|\+10:30|-03:30|-09:30|\+13:00|\+14:00|\+05:45|\+08:45|\+12:45))^((Z)|([\+\-])(\d\d):(\d\d))$

^ # use zero-width assertions to capture all the special cases:
(?!-00:00)                                    # not -00:00
(?=^(?:
   Z                                          # Z alone works,
   |[\+\-](?:0[0-9]|1[012]):00                # and all other +/- xx:00s,
   |\+0[34569]:30|\+10:30|-03:30|-09:30       # the +/- xx:30s.
   |\+13:00|\+14:00|\+05:45|\+08:45|\+12:45   # and these special cases
)) # Now that we've forced only positive matches, let's capture the pieces:
^(               # G1: the whole offset
  (Z) |             # G2: UTC indicator or nil
  ([\+\-])          # G3: +/- direction
  (\d\d)            # G4: "hours" part of offset
  :
  (\d\d)            # G5: "minutes" part of offset
)$
Submitted by Philip Flip Kromer