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match is Scala's killer feature — a switch-on-steroids that matches by structure, type, value, and conditions.

def describe(x: Any): String = x match {
  case 0          => "zero"
  case n: Int if n > 0 => s"positive: $n"
  case n: Int if n < 0 => s"negative: $n"
  case s: String  => s"a string of length ${s.length}"
  case _          => "something else"
}

Patterns:

• 0 — literal value
• n: Int — type pattern (binds the value as n)
• n if n > 0 — guard
• _ — wildcard (matches anything)
• Some(x), None — unapply patterns (work with case classes)
• (a, b) — tuple destructuring
• head :: tail — list destructuring

Matches are exhaustive when the compiler can verify it (e.g., on sealed traits). Non-exhaustive matches give a warning.