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

re = /(?:^(?:[A-Za-z0-9+\/]{4}\n?)*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)$)/ str = 'hQGkA8uYb/u24XuEAQzAh5dH2QUPv5rQ+uHwVQQShCgmgJzlOAq+L6Ld4l4P0MOeUYK7Zvt7HiYM MzH5Pdi+VfiW0JWDqTdvQZS6o0SfBzoZqwqplAofLH+7hlu8qS0n6FFxXk2b4N5InMf/zWlqpDb6 oeGZQBbLJy69drKzpJYvqMM+OuzLUA4Wwv/WfwGtHo/fQ3H2JSFwPJz3QHuqvTrnIhO23fZa8Qpd M36LBbX3yqrmrJo63NHy9QL9eF6+/WU7qsKOxGSm2QlDaREKx6ZlXgZ+FY7SEt1C6PHPXhggf4Ts EF5rb+0goEniDbgiofYpUt0+aLkwsNnMYHx0+yAelPP45ZbCKxQe1Tk3gq5oAspWvUAvt6SqmNW5 CrakBXYSIpNqHWdjdW75yeUYPKIi1X1SZi1mVGy0ayrOGoPbOY6C77JwGMxqEOZtDLBiy/u9g1II Zy1dm3UxhX/Tir2Cg+5kTAVQ6qqliklhGSCcYw0rNMfl+q151zKu4/j9id5pHnrkjnjrV1odz3u/ aBKxLpzf8cf2BlYdRooqvFIbdJULftmn0lABukKc0eaPclSdz//DzTU318fpHnFbzlUpi82UVNL4 IUqUviQNw7SX41v90N39iNP3JmczkN8J70+o7NLYlcvp4xXIFOcRaDrinbCcXT1WfQ==' # Print the match result str.match(re) do |match| puts match.to_s end

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 Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html