Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^([A-Za-z]{3} {1,2}[0-9]{1,2} {1,2}([0-9]{2}:){2}[0-9]{2}).* (delay=([0-9]{2}):([0-9]{2}):([0-9]{2})).*"; string substitution = @"\4\5\6 \1 \3"; string input = @"Mar 19 06:10:16 ip-172-2-0-53 sendmail[28131]: v2JDA1k4028131: to=root, ctladdr=root (0/0), delay=00:00:15, xdelay=00:00:00, mailer=relay, pri=30580, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (v2JDAG5W028134 Message accepted for delivery) Mar 19 14:41:26 ip-172-2-0-53 sendmail[29483]: v2JLfNFN029481: to=<tsturdsi@ifaded.com>,<kgogineni@ifaded.com>, delay=00:00:03, xdelay=00:00:03, mailer=esmtp, pri=151738, relay=ifaded-com.mail.p...ction.outlook.com. [xx.xxx.x.x], dsn=2.0.0, stat=Sent (<4253fc91a05d91ce3b5f5147278dfae9@heg.jkadionbub.com> [InternalId=31288836753166, Hostname=ERGDGD5.namprd07.prod.outlook.com] 8924 bytes in 0.309, 28.142 KB/sec Queued mail for delivery) Mar 19 06:10:26 ip-172-2-0-53 sendmail[28131]: v2JDA1k4028131: to=root, ctladdr=root (0/0), delay=00:20:15, xdelay=00:00:00, mailer=relay, pri=30580, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (v2JDAG5W028134 Message accepted for delivery) "; RegexOptions options = RegexOptions.Multiline; Regex regex = new Regex(pattern, options); string result = regex.Replace(input, substitution); } }

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