Generate random alphanumeric string in Swift

Question

How can I generate a random alphanumeric string in Swift?

Answer 1

Updated for Swift 4. Use a lazy stored variable on the class extension. This only gets computed once.

extension String {

    static var chars: [Character] = {
        return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".map({$0})
    }()

    static func random(length: Int) -> String {
        var partial: [Character] = []

        for _ in 0..