\W A non-word character
\s A whitespace character
\S A non-whitespace character
- \h An horizontal whitespace
+ \h A horizontal whitespace
\H A non horizontal whitespace
\N A non newline (when not followed by '{NAME}';;
not valid in a character class; equivalent to [^\n]; it's
(?&name) Recurse into a named subpattern
(?P>name) Recurse into a named subpattern (python syntax)
(?(cond)yes|no)
- (?(cond)yes) Conditional expression, where "cond" can be:
+ (?(cond)yes) Conditional expression, where "(cond)" can be:
(?=pat) lookahead
(?!pat) negative lookahead
(?<=pat) lookbehind