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| func unzip<S: Sequence, T, U>(_ sequence: S) -> (AnySequence<T>, AnySequence<U>) | |
| where S.Element == (T, U) | |
| { | |
| return ( | |
| AnySequence(sequence.lazy.map{ $0.0 }), | |
| AnySequence(sequence.lazy.map{ $0.1 }) | |
| ) | |
| } | |
| let fibonacci = sequence(first: (0, 1), next: { ($1, $0 + $1) }) | |
| let (withZero, withoutZero) = unzip(fibonacci) | |
| withZero // (0, 1, 1, 2, 3, 5, 8, 13, 21, 34 ... |
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A much less complex approach of course is just to map the sequence you want directly, without implementing the unzip function with generics:
let withZero = sequence(first: (0, 1), next:{ ($1, $0 + $1) }).lazy.map{ $0.0 }Based entirely on your example, not claiming any credit here, just pointing out the most simple path to the result. :)