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 (38)

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
  • 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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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

/
/
g

Unit Tests

given the string 10.1.1.1 assert that regex does match
given the string 10.255.255.255 assert that regex does match
given the string 101.0.26.90 assert that regex does not match
given the string 11.0.0.0 assert that regex does not match
given the string 111.211.73.40 assert that regex does not match
given the string 126.255.255.255 assert that regex does not match
given the string 127.0.0.0 assert that regex does match
given the string 127.255.255.255 assert that regex does match
given the string 128.0.0.0 assert that regex does not match
given the string 156.238.194.84 assert that regex does not match
given the string 164.101.185.82 assert that regex does not match
given the string 172.15.255.255 assert that regex does not match
given the string 172.16.0.0 assert that regex does match
given the string 172.31.255.255 assert that regex does match
given the string 172.32.0.0 assert that regex does not match
given the string 192.167.255.255 assert that regex does not match
given the string 192.168.0.0 assert that regex does match
given the string 192.168.255.255 assert that regex does match
given the string 192.169.0.0 assert that regex does not match
given the string 223.231.138.242 assert that regex does not match
given the string 226.84.185.150 assert that regex does not match
given the string 227.202.96.196 assert that regex does not match
given the string 250.29.143.180 assert that regex does not match
given the string 255.38.207.121 assert that regex does not match
given the string 44.37.112.180 assert that regex does not match
given the string 46.192.247.73 assert that regex does not match
given the string 71.12.102.112 assert that regex does not match
given the string 9.255.255.255 assert that regex does not match
given the string :: assert that regex does match
given the string ::1 assert that regex does match
given the string ::ffff:10.255.255.255 assert that regex does match
given the string ::ffff:127.255.255.255 assert that regex does match
given the string ::ffff:172.31.255.255 assert that regex does match
given the string ::ffff:192.168.255.255 assert that regex does match
given the string fe80::1 assert that regex does match
given the string http://localhost:8000 assert that regex does match
given the string http://lvh.me:8000 assert that regex does match
given the string http://192.168.1.103:8000/ assert that regex does match