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 = @"<\?xml(.+?)\?>"; string input = @"<?xml version=""1.0"" encoding=""utf-8""?> <ns1:StudySQL_response xmlns:ns1=""urn:global:cs:jdbc:study""> <Statement_response> <row> <XMLTYPE.GETSTRINGVAL(MESSAGE)>&lt;study studypid=&quot;200&quot;&gt; &lt;studyname&gt;&amp;quot;Immume Treat Phase3&amp;quot;&lt;/studyname&gt; &lt;statusCD&gt;ongoing&lt;/statusCD&gt; &lt;clinicalphase&gt;III&lt;/clinicalphase&gt; &lt;primaryIndication&gt;for lung cancer&lt;/primaryIndication&gt; &lt;startDate&gt;2010-Jun-28&lt;/startDate&gt; &lt;/study&gt; </XMLTYPE.GETSTRINGVAL(MESSAGE)> </row> <row> <XMLTYPE.GETSTRINGVAL(MESSAGE)>&lt;study studypid=&quot;201&quot;&gt; &lt;studyname&gt;&amp;quot;ABPM Study&amp;quot;&lt;/studyname&gt; &lt;statusCD&gt;on hold&lt;/statusCD&gt; &lt;clinicalphase&gt;III&lt;/clinicalphase&gt; &lt;primaryIndication&gt;skin cancel&lt;/primaryIndication&gt; &lt;startDate&gt;2015-Mar-08&lt;/startDate&gt; &lt;/study&gt; </XMLTYPE.GETSTRINGVAL(MESSAGE)> </row> </Statement_response> </ns1:StudySQL_response> "; 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