10.3.2 Groups

Specific information can be extracted from a matched string by using groups. If match() returns true, we can get groups using the matched(X) method, where X is the number of a group defined by regular expression pattern:

class Main {
  static function main() {
    var str = "Nicolas is 26 years old";
    var r =
      ~/([A-Za-z]+) is ([0-9]+) years old/;
    r.match(str);
    trace(r.matched(1)); // "Nicolas"
    trace(r.matched(2)); // "26"
  }
}

Note that group numbers start with 1 and r.matched(0) will always return the whole matched substring.

The r.matchedPos() will return the position of this substring in the original string:

class Main {
  static function main() {
    var str = "abcdeeeeefghi";
    var r = ~/e+/;
    r.match(str);
    trace(r.matched(0)); // "eeeee"
    // { pos : 4, len : 5 }
    trace(r.matchedPos());
  }
}

Additionally, r.matchedLeft() and r.matchedRight() can be used to get substrings to the left and to the right of the matched substring:

class Main {
  static function main() {
    var r = ~/b/;
    r.match("abc");
    trace(r.matchedLeft()); // a
    trace(r.matched(0)); // b
    trace(r.matchedRight()); // c
  }
}

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