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

/
/
gi

Test String

Code Generator

Language

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"<b>(?:(?!<\/?b>).)*?<\/b>(?:(?!<\/?b>).)*?<font color=darkslategray>.*?<\/font>"; string input = @"naive <b>na·ive</b><br><div style=""padding-left:0.5em;"">(<VR><span style=""color:#006400;font-style:italic"">or</span> <b>na·ïve</b></VR>) <font color=darkslategray>/nɑˈiːv, naıˈiːv/</font> <span style=""color:#006400;font-style:italic"">adj</span> [<i>more ~; most ~</i>]<br></div><div style=""padding-left:1em;""><b>:</b> having or showing a lack of experience or knowledge <b>:</b> innocent or simple<br></div><div style=""padding-left:1.5em;""><font color=""#004A95"">a <i>naive</i> belief that all people are good</font><br></div><div style=""padding-left:1.5em;""><font color=""#004A95"">a <i>naive</i> view of the world</font><br></div><div style=""padding-left:1.5em;""><font color=""#004A95"">I <i>naively</i> believed that we could fix the problem.</font><br></div><div style=""padding-left:1em;""><b>na·ïve·té</b> (<VR><span style=""color:#006400;font-style:italic"">also</span> <b>na·ive·te</b> <span style=""color:#006400;font-style:italic"">or</span> <b>na·ive·té</b></VR>) <font color=darkslategray>/nɑˌiːvˈteı, naıˌiːvˈteı/</font> <span style=""color:#006400;font-style:italic"">noun</span> [<span style=""color:#006400;font-style:italic"">noncount</span>]<br></div><div style=""padding-left:1.5em;""><font color=""#004A95"">political <i>naïveté</i></font><br></div><div style=""padding-left:1em;""><b>na·ive·ty</b> (<VR><span style=""color:#006400;font-style:italic"">also</span> <b>na·ïve·ty</b></VR>) <font color=darkslategray>/nɑˈiːvəti, naıˈiːvəti/</font> <span style=""color:#006400;font-style:italic"">noun</span> [<span style=""color:#006400;font-style:italic"">noncount</span>] <span style=""color:#006400;font-style:italic"">chiefly Brit</span><br></div><div style=""padding-left:1.5em;""><font color=""#004A95"">political <i>naïvety</i></font><br></div>"; RegexOptions options = RegexOptions.IgnoreCase; 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