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

/
/
gm

Test String

Code Generator

Language

Generated Code

re = /[0-9a-fA-F]{512}$/m str = '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 sadsfd3 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 dadadad sfsfsdgfdgfgfg 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' # Print the match result str.scan(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