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

/
/

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"(?:RTDM_Thread_Pool)"",(?:""\w+"":""[0-9A-Za-z-_]{1,}"",){1,}""__value_string__"":""[^""]+?metric=\'(rtmsasrtdm01.\w+ActiveThreads)"; string input = @"{""annotations"":{""DominosAlarm"":""RTDM_Thread_Pool"",""__alertId__"":""72"",""__alertScreenshotToken__"":""d011471d-3947-409b-8ea4-d74bfb288d11"",""__dashboardUid__"":""Do8Yh3jmk"",""__panelId__"":""2"",""__value_string__"":""[ var='A2' metric='rtmcrtsasrtdm01.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A3' metric='rtmcrtsasrtdm01.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A4' metric='rtmcrtsasrtdm01.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A5' metric='rtmcrtsasrtdm02.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A6' metric='rtmcrtsasrtdm02.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A7' metric='rtmcrtsasrtdm02.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A8' metric='rtminfsasrtdm01.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A9' metric='rtminfsasrtdm01.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A10' metric='rtminfsasrtdm01.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A11' metric='rtminfsasrtdm02.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A12' metric='rtminfsasrtdm02.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A13' metric='rtminfsasrtdm02.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A14' metric='rtmsasrtdm01.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A15' metric='rtmsasrtdm01.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A16' metric='rtmsasrtdm01.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A17' metric='rtmsasrtdm02.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A18' metric='rtmsasrtdm02.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A19' metric='rtmsasrtdm02.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A20' metric='rtmsasrtdm03.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A21' metric='rtmsasrtdm03.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A22' metric='rtmsasrtdm03.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A23' metric='rtmsasrtdm04.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A24' metric='rtmsasrtdm04.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A25' metric='rtmsasrtdm04.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A26' metric='rtmsasrtdm05.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A27' metric='rtmsasrtdm05.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A28' metric='rtmsasrtdm05.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A29' metric='rtmsasrtdm06.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A30' metric='rtmsasrtdm06.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A31' metric='rtmsasrtdm06.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A32' metric='NoData' labels={} value=null ]""},""endsAt"":""2022-08-15T14:51:09.011+03:00"",""fingerprint"":""07a1142e17b266ce"",""receivers"":[{""name"":""autogen-contact-point-default""}],""startsAt"":""2022-08-15T14:48:09.011+03:00"",""status"":{""inhibitedBy"":[],""silencedBy"":[],""state"":""active""},""updatedAt"":""2022-08-15T14:48:15.951+03:00"",""generatorURL"":""http://rtmsasanalys01.msk.mts.ru:3000/alerting/grafana/UzwGQ2kVz/view"",""labels"":{""Trigger"":""[ var='A0' metric='NoData' labels={} value=null ], [ var='A1' metric='NoData' labels={} value=null ], [ var='A2' metric='rtmcrtsasrtdm01.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A3' metric='rtmcrtsasrtdm01.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A4' metric='rtmcrtsasrtdm01.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A5' metric='rtmcrtsasrtdm02.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A6' metric='rtmcrtsasrtdm02.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A7' metric='rtmcrtsasrtdm02.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A8' metric='rtminfsasrtdm01.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A9' metric='rtminfsasrtdm01.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A10' metric='rtminfsasrtdm01.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A11' metric='rtminfsasrtdm02.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A12' metric='rtminfsasrtdm02.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A13' metric='rtminfsasrtdm02.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A14' metric='rtmsasrtdm01.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A15' metric='rtmsasrtdm01.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A16' metric='rtmsasrtdm01.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A17' metric='rtmsasrtdm02.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A18' metric='rtmsasrtdm02.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A19' metric='rtmsasrtdm02.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A20' metric='rtmsasrtdm03.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A21' metric='rtmsasrtdm03.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A22' metric='rtmsasrtdm03.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A23' metric='rtmsasrtdm04.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A24' metric='rtmsasrtdm04.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A25' metric='rtmsasrtdm04.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A26' metric='rtmsasrtdm05.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A27' metric='rtmsasrtdm05.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A28' metric='rtmsasrtdm05.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A29' metric='rtmsasrtdm06.ActivityThreadPool_ActiveThreads' labels={} value=null ], [ var='A30' metric='rtmsasrtdm06.JdbcOracle_ActiveThreads' labels={} value=null ], [ var='A31' metric='rtmsasrtdm06.JdbcSastkts_ActiveThreads' labels={} value=null ], [ var='A32' metric='NoData' labels={} value=null ]"",""__alert_rule_uid__"":""UzwGQ2kVz"",""alertname"":""RTDM Thread Pool alert"",""rule_uid"":""UzwGQ2kVz""}}"; Match m = Regex.Match(input, pattern); 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