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

Predefined character classes

Some character classes are so common that Raku gives them short names. You write them with a backslash:

• \d — a digit
• \w — a “word” character: a letter, a digit, or an underscore
• \s — a whitespace character (space, tab, newline)

say 'order 66' ~~ /\d/; # ｢6｣
say 'a_b'      ~~ /\w/; # ｢a｣
say '  hi'     ~~ /\s/; # ｢ ｣

Each of these has an upper-case partner that matches the opposite set:

• \D — anything that is not a digit
• \W — anything that is not a word character
• \S — anything that is not whitespace

say '  hi' ~~ /\S/; # ｢h｣

Finally, a single dot . matches any character at all:

say 'abc' ~~ /./; # ｢a｣

These predefined classes save a lot of typing, and you will use them constantly in the rest of this part.

Course navigation

← Quiz — Custom classes   |   Quiz — Character classes →

💪 Or jump directly to the exercises in this section.