Regular Expressions 101

Save & Share

  • Regex Version: ver. 4
  • 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

/
/
igm

Test String

Code Generator

Generated Code

using System; using System.Text.RegularExpressions; public class Example { public static void Main() { string pattern = @"^ *((#\d+)|((box|bin)[-. \/\\]?\d+)|(.*p[ \.]? ?(o|0)[-. \/\\]? *-?((box|bin)|b|(#|num)?\d+))|(p(ost)? *(o(ff(ice)?)?)? *((box|bin)|b)? *\d+)|(p *-?\/?(o)? *-?box)|post office (box|bin)|((box|bin)|b) *(number|num|#)? *\d+|(num|number|#) *\d+)"; string input = @"Valid: P. O. Box : Valid P.O.Box : Valid Post Box : Valid Post Office Box : Valid P.O.B : Valid P.O.B. : Valid POB : Valid Post Office Bin : Valid 100,, P O Box Des Moines : Valid P O Box DesMoines1000 : Valid P O Box Des Moines 1000 : Valid Post Office Box : Valid Post Office Box : Valid Post Box 123 : Valid PO P.O. P.B. Invalid: POTTER STREET"", ""Campbell Dr. Post Office : Invalid Box : Invalid Bin : Invalid Post : Invalid Postal Code : Invalid Portsmouth Campbell Raspberry Polonium Polar beer. 12 Box HC73 P.O. Box 217 P O Box 125 P. O. Box P.O. Box 123 P.O. Box p-o box Po Box POBOX123 p box Post Box 123 Post Office Box 123 Post Office Box Box 123 Box-122 Box122 box #123 box 122 box 123 P.O.B 123 P.O.B. 123 P.O.B. POB 123 POB Post 123 P.O 123 The Postal Road Box Hill 123 Some Street Controller's Office pollo St. 123 box canyon rd 777 Post Oak Blvd 123 box "; 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