func zip<S0 : SequenceType, S1 : SequenceType>(_: S0, s1: S1) A sequence of pairs built out of two underlying sequences, where the elements of the ith pair are the ith elements of each underlying sequence. Declaration func zip<S0 : SequenceType, S1 : SequenceType>(s0: S0, s1: S1) -> Zip2<S0, S1>