Regular Expressions 101

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Function

  • Match
  • Substitution
  • List
  • Unit Tests (9)

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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

/
/
gmi

Unit Tests

given the string WWW.DOMAIN.COM assert that regex does match
given the string WEB.DEV.DOMAIN.COM:1234 assert that regex does match
given the string DOMAIN.COM assert that regex does match
given the string domain.com.au assert that regex does match
given the string web.dev.domain.com:1234 assert that regex does match
given the string 127.0.0.1 assert that regex does not match
given the string 127.0.0.1:1234 assert that regex does not match
given the string localhost:1234 assert that regex does not match
given the string localhost assert that regex does not match