#21: Check if an Array Contains Elements in Swift

The idiomatic way to check whether an array contains at least one element is isEmpty.

let values = [1, 2, 3]
let empty: [Int] = []

!values.isEmpty // true
empty.isEmpty   // true

This is clearer than writing array.count > 0 and it also communicates your intent directly.

The same property is available on other collections too, so the pattern works with arrays, strings, sets, dictionaries and custom collection types.