Вот улучшение на ответ Shadow Of :
extension Collection where Self.Iterator.Element: RandomAccessCollection {
func transposed() -> [[Self.Iterator.Element.Iterator.Element]] {
guard let firstRow = self.first else { return [] }
return firstRow.indices.map { index in
self.map{ $0[index] }
}
}
}
let matrix = [
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12],
]
matrix.transposed().forEach{ print($0) }