Regular Expressions 101

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Function

  • Match
  • Substitution
  • List
  • Unit Tests (12)

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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
  • 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

/
/
gm

Unit Tests

given the string 211 assert that regex does match
given the string 311 assert that regex does match
given the string 411 assert that regex does match
given the string 511 assert that regex does match
given the string 611 assert that regex does match
given the string 711 assert that regex does match
given the string 811 assert that regex does match
given the string 911 assert that regex does match
given the string 5142811711 assert that regex does match
given the string 15142811711 assert that regex does match
given the string 05142811711 assert that regex does match
given the string 5145554321 assert that regex does not match