Step: Shorthand classes: \d \w \s

Common classes have shorthands: \d = digit [0-9], \w = word char [A-Za-z0-9_], \s = whitespace. Their uppercase forms negate: \D, \W, \S.

Why it matters: shorthands make patterns shorter and clearer than spelling out ranges.

Example: \d+ matches each run of digits.

Your turn: pull out every number with \d+.

Pitfall: \w includes the underscore and digits — it is not "letters only". For letters use [A-Za-z].