Meta Characters

\a

Match a BELL, \u0007.

\A

Match at the beginning of the input. Differs from ^ in that \A will not match after a new line within the input.

\b, outside of a [Set]

Match if the current position is a word boundary. Boundaries occur at the transitions between word (\w) and non-word (\W) characters, with combining marks ignored. For better word boundaries, see ICU Boundary Analysis.

\b, within a [Set]

Match a BACKSPACE, \u0008.

\B

Match if the current position is not a word boundary.

\cX

Match a control-X character.

\d

Match any character with the Unicode General Category of Nd (Number, Decimal Digit.).

\D

Match any character that is not a decimal digit.

\e

Match an ESCAPE, \u001B.

\E

Terminates a \Q ... \E quoted sequence.

\f

Match a FORM FEED, \u000C.

\G

Match if the current position is at the end of the previous match.

\n

Match a LINE FEED, \u000A.

\N{UNICODE CHARACTER NAME}

Match the named character.

\p{UNICODE PROPERTY NAME}

Match any character with the specified Unicode Property.

\P{UNICODE PROPERTY NAME}

Match any character not having the specified Unicode Property.

\Q

Quotes all following characters until \E.

\r

Match a CARRIAGE RETURN, \u000D.

\s

Match a white space character. White space is defined as [\t\n\f\r\p{Z}].

\S

Match a non-white space character.

\t

Match a HORIZONTAL TABULATION, \u0009.

\uhhhh

Match the character with the hex value hhhh.

\Uhhhhhhhh

Match the character with the hex value hhhhhhhh. Exactly eight hex digits must be provided, even though the largest Unicode code point is \U0010ffff.

\w

Match a word character. Word characters are [\p{Ll}\p{Lu}\p{Lt}\p{Lo}\p{Nd}].

\W

Match a non-word character.

\x{hhhh}

Match the character with hex value hhhh.

\xhh

Match the character with two digit hex value hh.

\X

Match a Grapheme Cluster. Partial implementation for ICU 2.4, does not handle Hangul syllables.

\Z

Match if the current position is at the end of input, but before the final line terminator, if one exists.

\z

Match if the current position is at the end of input.

\0nnn

Match the character with octal value nnn.

\n

Back Reference. Match whatever the nth capturing group matched. n must be > 1 and < total number of capture groups in the pattern.

[pattern]

Match any one character from the set. See UnicodeSet for a full description of what may appear in the pattern.

.

Match any character.

^

Match at the beginning of a line.

$

Match at the end of a line.

\

Quotes the following character. Characters that must be quoted to be treated as literals are * ? + [ ( ) { } ^ $