Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

r"
"
gim

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @": ([^\s]+)(?:[^\[]+)?\[([^:/]+[:/][^\s]+)(?:\s*l.[\d]+)?\] - ([a-f0-9]{24})?(?: - )?(.+)$"; string input = @"Nov 21 15:55:59 dasyure uwsgi.rtemail: INFO 18695 - [rtemail_base:process_m5e l.940] - 546f527f4b295f0ecb9a78b8 - ruid=ff6d4e50-dd2d-40c5-978c-0d8726674e4a m5e=66ae77250da162719d907a8d71bcceec from=mongodb ms=1 status=continue Nov 21 15:55:59 dasyure uwsgi.rtemail: INFO mule:18695 - [rtemail:process_in_exclusion l.355] - 546f527f4b295f0ecb9a78b8 - tagid=6545389 in_exclusion=false status=continue Nov 21 15:56:09 dasyure uwsgi.rtemail: DEBUG 18695 - [idents_message:__init__ l.22] - 546f527f4b295f0ecb9a78b8 - init_json json={'ruid': UUID('ff6d4e50-dd2d-40c5-978c-0d8726674e4a'), 'url': u'http://www.rueducommerce.fr/Ordinateurs/Ordinateur-Portable/Ordinateur-Portable-Grand-Public/APPLE/4920409-MacBook-Air-13-MD760F-B.htm#moid:MO-76BD5M31349632', 'ip': 127000000001, 'exclu': False, 'params': {'idproduit': [u'RSYS:30:4920409']}, 'message': {'google_cver': None, 'accept_cookies': True, 'ident': '6545389_ff6d4e50-dd2d-40c5-978c-0d8726674e4a_66ae77250da162719d907a8d71bcceec', 'ggruid': 3658, 'r1': (False, UUID('ff6d4e50-dd2d-40c5-978c-0d8726674e4a'), False), 'r3': (False, UUID('ff6d4e50-dd2d-40c5-978c-0d8726674e4a'), False), 'eulerian_uid': None, 'sync': [], 'tagid': 6545389, 'utcnow': datetime.datetime(2014, 11, 21, 14, 55, 59, tzinfo=<bson.tz_util.FixedOffset object at 0x7f3edfa707d0>), 'new_cookie': False, 'adnxs_uid': None, 'action': 3, 'google_gid': None, 'ck1add': {}, 'now': datetime.datetime(2014, 11, 21, 15, 55, 59, 329577), 'cpu': {'stats': False, 'pixel': False, 'syncJS': False, 'syncJarM5e': False}}, '_id': ObjectId('546f527f4b295f0ecb9a78b8'), 'ua': u'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.111 Safari/537.36'} Nov 21 15:56:09 dasyure uwsgi.rtemail: INFO 18695 - [rtemail_base_client:process_is_expired l.90] - 546f527f4b295f0ecb9a78b8 - expired=false status=continue"; RegexOptions options = RegexOptions.IgnoreCase | RegexOptions.Multiline; foreach (Match m in Regex.Matches(input, pattern, options)) { Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index); } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx