Pairwise in Swift

gistfile1.swift

func pairwise<T>(d: [T]) -> [(T,T)] {
    switch d.count {
    case 0: return []
    case 1: return []
    case let n:
        let r = [(d[0],d[1])]
        return r + pairwise(Array(d[1..<n]))
    }
}


let info = [1,2,3,4,5,6]
let info2 = ["A","B","C","D"]

pairwise(info)      // (1,2) (2,3) (3,4) (4,5) (5,6)
pairwise(info2)     // (A,B) (B,C) (C,D)
pairwise([Int]())   // []
pairwise(["A"])     // []