| Construct |
Matches |
| ? |
| Characters |
|
x
|
The character x |
|
\\
|
The backslash character |
|
\0
n
|
The character with octal value 0n (0?<=?n?<=?7) |
|
\0
nn
|
The character with octal value 0nn (0?<=?n?<=?7) |
|
\0
mnn
|
The character with octal value 0mnn (0?<=?m?<=?3, 0?<=?n?<=?7) |
|
\x
hh
|
The character with hexadecimal?value?0xhh |
|
\u
hhhh
|
The character with hexadecimal?value?0xhhhh |
|
\t
|
The tab character ('\u0009') |
|
\n
|
The newline (line feed) character ('\u000A') |
|
\r
|
The carriage-return character ('\u000D') |
|
\f
|
The form-feed character ('\u000C') |
|
\a
|
The alert (bell) character ('\u0007') |
|
\e
|
The escape character ('\u001B') |
|
\c
x
|
The control character corresponding to x |
| ? |
| Character classes |
|
[abc]
|
a, b, or c (simple class) |
|
[^abc]
|
Any character except a, b, or c (negation) |
|
[a-zA-Z]
|
a through z or A through Z, inclusive (range) |
|
[a-d[m-p]]
|
a through d, or m through p: [a-dm-p] (union) |
|
[a-z&&[def]]
|
d, e, or f (intersection) |
|
[a-z&&[^bc]]
|
a through z, except for b and c: [ad-z] (subtraction) |
|
[a-z&&[^m-p]]
|
a through z, and not m through p: [a-lq-z](subtraction) |
| ? |
| Predefined character classes |
|
.
|
Any character (may or may not match line terminators) |
|
\d
|
A digit: [0-9] |
|
\D
|
A non-digit: [^0-9] |
|
\s
|
A whitespace character: [ \t\n\x0B\f\r] |
|
\S
|
A non-whitespace character: [^\s] |
|
\w
|
A word character: [a-zA-Z_0-9] |
|
\W
|
A non-word character: [^\w] |
| ? |
| POSIX character classes (US-ASCII only) |
|
\p{Lower}
|
A lower-case alphabetic character: [a-z] |
|
\p{Upper}
|
An upper-case alphabetic character:[A-Z] |
|
\p{ASCII}
|
All ASCII:[\x00-\x7F] |
|
\p{Alpha}
|
An alphabetic character:[\p{Lower}\p{Upper}] |
|
\p{Digit}
|
A decimal digit: [0-9] |
|
\p{Alnum}
|
An alphanumeric character:[\p{Alpha}\p{Digit}] |
|
\p{Punct}
|
Punctuation: One of !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~ |
|
\p{Graph}
|
A visible character: [\p{Alnum}\p{Punct}] |
|
\p{Print}
|
A printable character: [\p{Graph}\x20] |
|
\p{Blank}
|
A space or a tab: [ \t] |
|
\p{Cntrl}
|
A control character: [\x00-\x1F\x7F] |
|
\p{XDigit}
|
A hexadecimal digit: [0-9a-fA-F] |
|
\p{Space}
|
A whitespace character: [ \t\n\x0B\f\r] |
| ? |
| java.lang.Character classes (simple java character type) |
|
\p{javaLowerCase}
|
Equivalent to java.lang.Character.isLowerCase() |
|
\p{javaUpperCase}
|
Equivalent to java.lang.Character.isUpperCase() |
|
\p{javaWhitespace}
|
Equivalent to java.lang.Character.isWhitespace() |
|
\p{javaMirrored}
|
Equivalent to java.lang.Character.isMirrored() |
| ? |
| Classes for Unicode blocks and categories |
|
\p{InGreek}
|
A character in the Greek?block (simple block) |
|
\p{Lu}
|
An uppercase letter (simple category) |
|
\p{Sc}
|
A currency symbol |
|
\P{InGreek}
|
Any character except one in the Greek block (negation) |
|
[\p{L}&&[^\p{Lu}]]?
|
Any letter except an uppercase letter (subtraction) |
| ? |
| Boundary matchers |
|
^
|
The beginning of a line |
|
$
|
The end of a line |
|
\b
|
A word boundary |
|
\B
|
A non-word boundary |
|
\A
|
The beginning of the input |
|
\G
|
The end of the previous match |
|
\Z
|
The end of the input but for the final terminator, if?any |
|
\z
|
The end of the input |
| ? |
| Greedy quantifiers |
|
X
?
|
X, once or not at all |
|
X
*
|
X, zero or more times |
|
X
+
|
X, one or more times |
|
X
{
n
}
|
X, exactly n times |
|
X
{
n
,}
|
X, at least n times |
|
X
{
n
,
m
}
|
X, at least n but not more than m times |
| ? |
| Reluctant quantifiers |
|
X
??
|
X, once or not at all |
|
X
*?
|
X, zero or more times |
|
X
+?
|
X, one or more times |
|
X
{
n
}?
|
X, exactly n times |
|
X
{
n
,}?
|
X, at least n times |
|
X
{
n
,
m
}?
|
X, at least n but not more than m times |
| ? |
| Possessive quantifiers |
|
X
?+
|
X, once or not at all |
|
X
*+
|
X, zero or more times |
|
X
++
|
X, one or more times |
|
X
{
n
}+
|
X, exactly n times |
|
X
{
n
,}+
|
X, at least n times |
|
X
{
n
,
m
}+
|
X, at least n but not more than m times |
| ? |
| Logical operators |
|
XY
|
X followed by Y |
|
X
|
Y
|
Either X or Y |
|
(
X
)
|
X, as a capturing group |
| ? |
| Back references |
|
\
n
|
Whatever the nthcapturing group matched |
| ? |
| Quotation |
|
\
|
Nothing, but quotes the following character |
|
\Q
|
Nothing, but quotes all characters until \E |
|
\E
|
Nothing, but ends quoting started by \Q |
| ? |
| Special constructs (non-capturing) |
|
(?:
X
)
|
X, as a non-capturing group |
|
(?idmsux-idmsux)?
|
Nothing, but turns match flags on - off |
|
(?idmsux-idmsux:
X
)?? |
X, as a non-capturing group with the given flags on - off |
|
(?=
X
)
|
X, via zero-width positive lookahead |
|
(?!
X
)
|
X, via zero-width negative lookahead |
|
(?<=
X
)
|
X, via zero-width positive lookbehind |
|
(?<!
X
)
|
X, via zero-width negative lookbehind |
|
(?>
X
)
|
X, as an independent, non-capturing group |