Meta character | Meaning | |
|
{n} | Exactly n times | |
{n,} | At least n times | |
{n,m} | At least n but not more than m times | |
(?=expression) | Positive lookahead | |
(?!expression) | Negative lookahead | |
(?<=expression) | Positive lookbehind | |
(?<!expression) | Negative lookbehind | |
\1 \2 ... | Backreference | |
*? +? ?? {n,m}? | Reluctant quantifiers | |
(?\tag-number) | Match target | |
\s | Same as[ \t\r\n] | |
\S | Same as[^ \t\r\n] | |
\d | Same as [0-9] | |
\D | Same as [^0-9] | |
\c | Same as [a-zA-Z0-9_] | |
\C | Same as [^a-zA-Z0-9_] | |
\i | Same as [a-zA-Z_] | |
\I | Same as [^a-zA-Z_] | |
\y | Word boundaries with number | |
\Y | Negated version of \y | |
\Q to \E | Between the \Q and the \E are interpreted as literal characters | |
(?:expression) | Non-capturing groups | |
(?#expression) | Comment | |