java.util.regex.Pattern - general question

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Angus Parvis - 02 Nov 2003 01:34 GMT

What is the difference between greedy, reluctant and posessive quantifiers?

To me it seems that there's no difference in writing "X(n,m)", "X(n,m)?"
or "X(n,m)+". Maybe you could give me a hint what the difference is.

Thanks in advance for sharing your knowledge ;)

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Thomas Schodt - 02 Nov 2003 07:56 GMT

> What is the difference between greedy, reluctant and posessive
> quantifiers?

Greedy
? try to match 1, 0 is ok (*1)
* try to match many, 0 is ok (*1)
+ try to match many, 1 is ok (*1)

Reluctant
+? try to match 1, more is ok (*1)
*? try to match 0, more is ok (*1)

(*1) if necessary to make the pattern match

> X(n,m)

as you would expect, match n to m

> X(n,m)?

match n to m, or none

> X(n,m)+

match n to m, one or more times

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