Course of Raku / Regexes and grammars / Regexes / Literals and character classes

Character classes

Often you do not want to match one fixed character but any character out of a set. Such a set is called a character class and is written between <[ and ]>:

say 'grey' ~~ / gr <[ae]> y /; # ｢grey｣
say 'gray' ~~ / gr <[ae]> y /; # ｢gray｣

The class <[ae]> matches a single character that is either a or e, so both spellings of the colour — or color, if you prefer — match.

Inside the brackets you can list a range with two dots:

say 'a1b2' ~~ / <[0..9]> /; # ｢1｣

<[0..9]> matches any one digit; the first digit in the string is 1.

To match any character that is not in the set, put a minus sign right after the opening bracket:

say 'stop!' ~~ / <-[a..z]> /; # ｢!｣

Here <-[a..z]> matches the first character that is not a lowercase letter, which is the exclamation mark.

You can combine several pieces in one class. For example, <[a..z A..Z 0..9]> matches a letter or a digit. The spaces there are only for readability — as everywhere in a regex, spaces inside <[…]> are ignored, so <[a..zA..Z0..9]> is exactly the same class.

Course navigation

← Matching literal text   |   Quiz — Custom classes →

💪 Or jump directly to the exercises in this section.