DEELX Basic Pattern Syntax: Repeat Quantifier

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Repeat Quantifier

Make another expression repeat matching many times.

Remarks

Can make other expression repeat matching fixed times and various times.

By default, a quantified subpattern is "greedy", that is, it will match as many times as possible (given a particular starting location) while still allowing the rest of the pattern to match.

Quantifier	Description
{n}	Repeat fixed n times, example: "\w{2}" equivalent to "\w\w"
{m, n}	Match n times if possible, m times least, example: "ba{1,3}" can "ba","baa","baaa"
{m, }	As many as possible, m times least, example: "\w\d{2,}" can "a12","x456"...
?	Match 1 time if possible, 0 time if could not match, equivalent to {0, 1}
+	As many as possible, 1 times least, equivalent to {1, }
*	As many as possible, 0 times if could not match, equivalent to {0, }

"Reluctant" quantifier:

If a quantifier is followed by a question mark(?), it becomes a "reluctant" quantifier. Reluctant quantifiers will match the minimum number of times possible.

Quantifier	Description
{m, n}?	Match only m times if possible, at most n times.
{m, }?	Match only m times if possible, can match as many times as necessary.
??	Match 0 time if possible, at most 1 time, equivalent to {0, 1}?
+?	Match only 1 time if possible, can match as many times as necessary, {1, }?
*?	Match 0 time if possible, can match as many times as necessary, {0, }?

"Possessive" quantifiers:

If a quantifier is followed by a plus(+), it becomes a "possessive" quantifiers. Possessive quantifiers, which greedily match as much as they can and do not back off, even when doing so would allow the overall match to succeed.

Quantifier	Description
{m, n}+	Match n times if possible, m times at least.
{m, }+	As many times as possible, m times at least.
?+	Match 1 time if possible, match 0 time if could not, equivalent to {0, 1}+
++	As many as possible, 1 times least, equivalent to {1, }+
*+	As many as possible, 0 times if could not match, equivalent to {0, }+