Java examples for Regular Expressions:Pattern
| Syntax | Matches |
|---|---|
| x | character x. |
| \p | punctuation character p. |
| \\ | backslash character. |
| \n | newline character \u000A. |
| \t | tab character \u0009. |
| \r | carriage return character \u000D. |
| \f | form feed character \u000C. |
| \e | escape character \u001B. |
| \a | bell character \u0007. |
| \uhhhh | Unicode character with hexadecimal code hhhh. |
| \xhh | character with hexadecimal code hh. |
| \0n | character with octal code n. |
| \0nn | character with octal code nn. |
| \0nnn | Character with octal code nnn, in which nnn <= 377. |
| \cx | control character ^x. |
| Syntax | Matches |
|---|---|
| [...] | One of the characters between the brackets. |
| [^...] | Any one character not between the brackets. |
| [a-z0-9] | The character range: a character between (inclusive) a and z or 0 and 9. |
| [0-9[a-fA-F]] | The union of classes: same as [0-9a-fA-F]. |
| [a-z&&[aeiou]] | The intersection of classes: same as [aeiou]. |
| [a-z&&[^aeiou]] | Subtraction: the characters a through z, except for the vowels. |
| . | Any character, except a line terminator. If the DOTALL flag is set, it matches any character, including line terminators. |
| \d | An ASCII digit: [0-9]. |
| \D | Anything but an ASCII digit: [^\d]. |
| \s | ASCII whitespace: [ \t\n\f\r\x0B]. |
| \S | Anything but ASCII whitespace: [^\s]. |
| \w | An ASCII word character: [a-zA-Z0-9_]. |
| \W | Anything but an ASCII word character: [^\w]. |
| \p{group} | Any character in the named group. |
| \P{group} | Any character not in the named group. |
| \p{Lower} | An ASCII lowercase letter: [a-z]. |
| \p{Upper} | An ASCII uppercase letter: [A-Z]. |
| \p{ASCII} | Any ASCII character: [\x00-\x7f] |
| \p{Alpha} | An ASCII letter: [a-zA-Z]. |
| \p{Digit} | An ASCII digit: [0-9] |
| \p{XDigit} | A hexadecimal digit: [0-9a-fA-F]. |
| \p{Alnum} | ASCII letter or digit: [\p{Alpha}\p{Digit}]. |
| \p{Punct} | ASCII punctuation: one of !"#$%&'( )*+,-./:;<=>?@[\]^_`{|}~]. |
| \p{Graph} | A visible ASCII character: [\p{Alnum}\p{Punct}]. |
| \p{Print} | A visible ASCII character: same as \p{Graph}. |
| \p{Blank} | An ASCII space or tab: [ \t]. |
| \p{Space} | ASCII whitespace: [ \t\n\f\r\x0b]. |
| \p{Cntrl} | An ASCII control character: [\x00-\x1f\x7f]. |
| \p{category} | Any character in the named Unicode category. One-letter codes include L for letter, N for number, S for symbol, Z for separator, and P for punctuation. Two-letter codes represent subcategories, such as Lu for uppercase letter, Nd for decimal digit, Sc for currency symbol, Sm for math symbol, and Zs for space separator. |
| \p{block} | Any character in the named Unicode block. In Java regular expressions, block names begin with "In", followed by mixed-case capitalization of the Unicode block name, without spaces or underscores. For example: \p{InOgham} or \p{In Mathematical Operators}. |
| Syntax | Matches |
|---|---|
| xy | Match x followed by y. |
| x |y | Match x or y. |
| (...) | Group subexpression within parentheses into a single unit that can be used with * , + , ?, | , and so on. |
| (?:...) | Grouping only. Group subexpression as with ( ), but do not capture the text that matched. |
| \n | Match the same characters that were matched when capturing group number n was first matched. |
| Syntax | Matches |
|---|---|
| x? | Zero or one occurrence of x; i.e., x is optional. |
| x* | Zero or more occurrences of x. |
| x+ | One or more occurrences of x. |
| x{n} | Exactly n occurrences of x. |
| x{n,} | n or more occurrences of x. |
| x{n,m} | At least n, and at most m occurrences of x |
| Syntax | Matches |
|---|---|
| ^ | beginning of the input string or, if the MULTILINE flag is specified, the beginning of the string or of any new line. |
| $ | end of the input string or, if the MULTILINE flag is specified, the end of the string or of line within the string. |
| \b | A word boundary |
| \B | A position in the string that is not a word boundary. |
| \A | The beginning of the input string. Like ^, but never matches the beginning of a new line, regardless of what flags are set. |
| \Z | The end of the input string, ignoring any trailing line terminator. |
| \z | The end of the input string, including any line terminator. |
| \G | The end of the previous match. |
| (?=x) | A positive look-ahead assertion. |
| (?!x) | A negative look-ahead assertion. |
| (?<=x) | A positive look-behind assertion. |
| (?<!x) | A negative look-behind assertion. |
| Syntax | Matches |
|---|---|
| (?>x) | Match x independently of the rest of the expression. |
| (?onflags-offflags) | Don't match anything, but turn on the flags specified by onflags, and turn off the flags specified by offflags. |
| (?onflags-offflags:x) | Match x, applying the specified flags to this subexpression only. This is a noncapturing group, such as (?:...), with the addition of flags. |
| \Q | Don't match anything, but quote all subsequent pattern text until \E. |
| \E | Don't match anything; terminate a quote started with \Q. |
| #comment | If the COMMENT flag is set, pattern text between a # and the end of the line is considered a comment and is ignored. |