Swift - Determine if Array1 contains at least one object from Array2

Question

I have 2 Arrays. Say, array1 = [1,2,3,4,5] and array2 = [2,3]. How could I check in swift if array1 contains at least one item from

Answer 1

let a1 = [1, 2, 3]
let a2 = [2, 3, 4]

Option 1

a2.filter { a1.contains($0) }.count > 1

Option 2

a2.reduce(false, combine: { $0 || a1.contains($1) })