XSLT, 2nd Edition

Quantifiers

A quantifier specifies how many times (or if) something occurs. There are three quantifier characters and a syntax for specifying quantities more explicitly. For example, (a|b)?c matches ac, bc, and c, because the question mark indicates zero or one instances of a pattern. Here are all the quantifiers and their syntax:

?

Zero or one of a pattern.

*

Zero or more of a pattern.

+

One or more of a pattern.

{x}

The pattern must occur exactly x times. The pattern (a|b){3} matches aaa and abb, but not ab.

{x,}

The pattern must occur at least x times. The pattern (a|b){3,} matches aaa and aaaaaaaaa, but not aa.

{x,y}

The pattern must occur at least x times, but no more than y times. The pattern (a|b){2,5} matches aa and aaa, but not aaaaaa.