Pattern Matching with Regular Expressions - Java - page 128

Subexpression Matches Notes

{ , n }+

Possessive quantifier for 0 up to n repeti-
tions

Possessive quantifier: 0 or more \*+

Possessive quantifier: 1 or more ++

Possessive quantifier: 0 or 1 times

?+

Escapes and shorthands

Escape (quote) character: turns most
metacharacters off; turns subsequent alpha-
betic into metacharacters

\

Escape (quote) all characters up to \E

\Q

Ends quoting begun with \Q

\E

Tab character \t

Return (carriage return) character \r

Newline character See Matching Newlines in Text

\n

Form feed \f

Character in a word Use \w+ for a word; see Program:

Apache Logfile Parsing

\w

A nonword character

\W

Numeric digit Use \d+ for an integer; see Using

regexes in Java: Test for a Pattern

\d

A nondigit character \D

Whitespace Space, tab, etc., as determined by

java.lang.Character.isWhitespace()

\s

A nonwhitespace character See Program: Apache Logfile

Parsing

\S