Regular Expressions 101

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Function

  • Match
  • Substitution
  • List
  • Unit Tests (10)

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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

/
/

Unit Tests

given the string some.path\\to\\a\\kind.of.file.ext\\ assert that regex does not match
given the string some.path/to/a/kind.of.file.ext/ assert that regex does not match
given the string some.path\\to\\a\\kind.of.file.ext assert that full match equals .ext
given the string some.path/to/a/kind.of.file.ext assert that full match equals .ext
given the string somepath\\to\\a\\file.ext assert that full match equals .ext
given the string somepath/to/a/file.ext assert that full match equals .ext
given the string js-name.js assert that full match equals .js
given the string somename.something.html assert that full match equals .html
given the string filename.ext assert that full match equals .ext
given the string something.png assert that full match equals .png