+NSStringisStringidstr ifstr isKindOfClassNSNull class str isEqualNSNull null str==nil return ; else return NSString stringWithFormatstr; +NSArrayisArrayidarr ifarr

func isString(_ str: Any?) -> String { if let str = str as? NSNull { return "" } else if let str = str as? String { return str } else { return "" } }

func isArray(_ arr: Any?) -> [Any] { if let arr = arr as? NSNull { return [] } else if let arr = arr as? [Any] { return arr } else { return [] } }

func isDic(_ dic: Any?) -> [String: Any] { if let dic = dic as? NSNull { return [:] } else if let dic = dic as? [String: Any] { return dic } else { return [:] }