Regular Expressions 101

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Function

  • Match
  • Substitution
  • List
  • Unit Tests (15)

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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

r"
"
gm

Unit Tests

valid simple slug matches
multiple valid slugs separated by slashes match
last slash is optional matches
missing initial slash does not match
valid slug with extra whitespace does not match
blank spaces as separators do not match
invalid characters in slug do not match
single slash does not match
nothing does not match
exactly 64 valid slugs match
more than 64 slugs do not match
slug exactly 255 characters long matches
slug with more than 255 characters does not match
exactly 64 valid slugs 255 characters long each matches
more than 64 slugs 255 characters long each does not match