ArrayType in extension where clause

Question

extension Array where Element: _ArrayType, Element.Generator.Element: Any {
    func transpose() -> [Element] {
        if self.isEmpty { return [Element]() }
        let count = self[0].count
        var out = [Element](repeating: Element(), count: count)
        for outer in self {
            for (index, inner) in outer.enumerated() {
                out[index].append(inner)
            }
        }
        return out
    }
}

I am getting this error in Swift 3.0 after converting it from Swift 2.2. The elements of the array are also array. So how to define it in Swift 3.0?

Have a look at http://stackoverflow.com/questions/39179660/swift-2d-array-generic-extension-issue-accessing-2nd-dimension, it should be easy to modify that code for your needs. — Martin R, Sep 07 '16 at 10:58

score 0 · Answer 1 · edited Jun 08 '17 at 04:25

extension Array where Element : Collection, Element.Index == Int, Element.IndexDistance == Int {
    func transpose() -> [[Element.Iterator.Element]] {
        typealias InnerElement = Element.Iterator.Element
        if self.isEmpty { return [] }
        let count = self[0].count
        var out = [[InnerElement]](repeating: [InnerElement](), count: count)
        for outer in self {
            for (index, inner) in outer.enumerated() {
                out[index].append(inner)
            }
        }
        return out
    }
}

ArrayType in extension where clause

1 Answers1