regex - KeynesYouDigIt/Knowledge GitHub Wiki

Character Classes

. - Single character
<character>* - 0 or more of the character before the * (greedy- matches full string, then backtracks)
<character>*? - 0 or more of the character before the * (lazy- matches nothing, moves forward)
<character>*+ - 0 or more of the character before the * (possessive, matches full string, no backtrack)
<character>+ - 1 or more of the character before the +
<character>? - 0 or 1 of the character before the ?
<character>{2} - 2 of the character before the {2}
<character>{2,} - 2 or more of the character before the {2,}
<character>{2,4} - 2, 3, or 4 character before the {2,4}
^<character> - Must be the beginning of the line
[^character] - Not
(this|that) - Or
$ - Must be the end of the line
\ - Escape
- - Range (a-z, A-Z, 0-9)
[<characters>] - Sets and options
- A character set will match any individual item in it
\s - Whitespace
\S - Non-whitespace
\d - Digit
\D - Non-digit
\b - Word boundary
\B - Non-word boundary
\w - Word character
\W - Non-word character
$<some term>$ - Save a back reference
\1 - Back reference
q(?!u) - Negative lookahead (q not followed by u)
q(?-u) = positive lookahead (q followed by a u)