General |
^ | Start of line/string | |
$ | End of line/string | |
\b | Word boundary | |
\B | Not a word boundary | |
\A | Beginning of entire string | |
\z | End of entire string | |
\Z | End of entire string (except allowable final line terminator) |
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. | Any one character (except line terminator) | |
[...] | "Character class"; any one character from those listed | |
[^...] | Any one character not from those listed |
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Alternation and grouping |
(...) | Grouping (capture groups) |
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| | Alternation | |
(?:re) | Noncapturing parenthesis | |
\G | End of the previous match | |
\n | Back-reference to capture group number "n" | |
Normal (greedy) multipliers |
{m,n} | Multiplier for "from m to n repetitions" |
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{m,} | Multiplier for "m or more repetitions" | |
{m} | Multiplier for "exactly m repetitions" |
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{,n} | Multiplier for 0 up to n repetitions | |
* | Multiplier for 0 or more repetitions | Short for {0,} |
+ | Multiplier for 1 or more repetitions | Short for {1,} |
? | Multiplier for 0 or 1 repetitions (i.e, present exactly once, or not at all) | Short for {0,1} |
Reluctant (non-greedy) multipliers |
{m,n}? | Reluctant multiplier for "from m to n repetitions" | |
{m,}? | Reluctant multiplier for "m or more repetitions" | |
{,n}? | Reluctant multiplier for 0 up to n repetitions | |
*? | Reluctant multiplier: 0 or more | |
+? | Reluctant multiplier: 1 or more |
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?? | Reluctant multiplier: 0 or 1 times | |
Possessive (very greedy) multipliers |
{m,n}+ | Possessive multiplier for "from m to n repetitions" | |
{m,}+ | Possessive multiplier for "m or more repetitions" | |
{,n}+ | Possessive multiplier for 0 up to n repetitions | |
*+ | Possessive multiplier: 0 or more | |
++ | Possessive multiplier: 1 or more | |
?+ | Possessive multiplier: 0 or 1 times | |
Escapes and shorthands |
\ | Escape (quote) character: turns most metacharacters off; turns subsequent alphabetic into metacharacters | |
\Q | Escape (quote) all characters up to \E | |
\E | Ends quoting begun with \Q | |
\t | Tab character | |
\r | Return (carriage return) character | |
\n | Newline character |
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\f | Form feed | |
\w | Character in a word | Use \w+ for a word; |
\W | A non-word character | |
\d | Numeric digit | Use \d+ for an integer; |
\D | A non-digit character | |
\s | Whitespace | Space, tab, etc., as determined by java.lang.Character.isWhitespace( ) |
\S | A nonwhitespace character |
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Unicode blocks (representative samples) |
\p{InGreek} | A character in the Greek block | (simple block) |
\P{InGreek} | Any character not in the Greek block | |
\p{Lu} | An uppercase letter | (simple category) |
\p{Sc} | A currency symbol | |
POSIX-style character classes (defined only for US-ASCII) |
\p{Alnum} | Alphanumeric characters | [A-Za-z0-9] |
\p{Alpha} | Alphabetic characters | [A-Za-z] |
\p{ASCII} | Any ASCII character | [\x00-\x7F] |
\p{Blank} | Space and tab characters | |
\p{Space} | Space characters | [ \t\n\x0B\f\r] |
\p{Cntrl} | Control characters | [\x00-\x1F\x7F] |
\p{Digit} | Numeric digit characters | [0-9] |
\p{Graph} | Printable and visible characters (not spaces or control characters) | |
\p{Print} | Printable characters | Same as \p{Graph} |
\p{Punct} | Punctuation characters | One of !"#$%&'( )*+,-./:;<=>?@[\]^_`{|}~ |
\p{Lower} | Lowercase characters | [a-z] |
\p{Upper} | Uppercase characters | [A-Z] |
\p{XDigit} | Hexadecimal digit characters | [0-9a-fA-F] |