Extending Array to check if it is sorted in Swift?

Question

I want to extend Array class so that it can know whether it is sorted (ascending) or not. I want to add a computed property called isSorted. How can I state the

Answer 1

The generic function, zip(), can provide a shortcut for implementation.

extension Collection where Element: Comparable {
    var isSorted: Bool {
        guard count > 1 else {
            return true 
        }

        let pairs = zip(prefix(count - 1), suffix(count - 1))

        return !pairs.contains { previous, next in
            previous > next
        }
    }
}

[0, 1, 1, 2].isSorted  // true
[0, 2, 2, 1].isSorted  // false