swift4.2 中字符串按照字符存成数组(字符串转数组)

 class func stringToArray(input:NSString) ->NSArray {

        let arrInput = (0..<input.length).map({

            Character(UnicodeScalar(input.character(at: $0))!)

        })

        return arrInput as NSArray

    }

or

 class func stringToArray(input:String) ->Array {

         return  input.map { String($0) }

    }