Pattern Matching with Regular Expressions - Java - page 127

Subexpression Matches Notes

{ m , n }

Quantifier for “from m to n repetitions” See Replacing the Matched Text

Quantifier for " m or more repetitions”

{ m ,}

Quantifier for “exactly m repetitions” See Program: Apache Logfile

Parsing

{ m }

{ , n }

Quantifier for 0 up to n repetitions

Quantifier for 0 or more repetitions Short for {0,} \*

Quantifier for 1 or more repetitions Short for {1,} ; see Using regexes

in Java: Test for a Pattern

+

Quantifier for 0 or 1 repetitions (i.e.,
present exactly once, or not at all)

Short for {0,1}

?

Reluctant (non-greedy)
quantifiers

{ m , n }? Reluctant quantifier for “from m to n repeti-

tions”

Reluctant quantifier for " m or more repeti-
tions”

{ m ,}?

{ , n }?

Reluctant quantifier for 0 up to n repetitions

Reluctant quantifier: 0 or more

\*?

Reluctant quantifier: 1 or more See Program: Apache Logfile

Parsing

+?

Reluctant quantifier: 0 or 1 times ??

Possessive (very greedy)
quantifiers

{ m , n }+ Possessive quantifier for “from m to n repeti-

tions”

Possessive quantifier for " m or more repeti-
tions”

{ m ,}+