我想检查泛型类类型是否为数组:
func test<T>() -> Wrapper<T> { let isArray = T.self is Array<Any> ... }
但它警告说
Cast from ‘T.type’ to unrelated type ‘Array’ always fails
我怎么解决这个问题?
补充:我已将我的代码上传到Gist.
https://gist.github.com/nallwhy/6dca541a2d1d468e0be03c97add384de
解决方法
正如评论员@Holex所说,你可以使用Any.将它与Mirror结合使用,例如,您可以执行以下操作:
func isitacollection(_ any: Any) -> [String : Any.Type]? { let m = Mirror(reflecting: any) switch m.displayStyle { case .some(.collection): print("Collection,\(m.children.count) elements \(m.subjectType)") var types: [String: Any.Type] = [:] for (_,t) in m.children { types["\(type(of: t))"] = type(of: t) } return types default: // Others are .Struct,.Class,.Enum print("Not a collection") return nil } } func test(_ a: Any) -> String { switch isitacollection(a) { case .some(let X): return "The argument is an array of \(X)" default: return "The argument is not an array" } } test([1,2,3]) // The argument is an array of ["Int": Swift.Int] test([1,"3"]) // The argument is an array of ["Int": Swift.Int,"String": Swift.String] test(["1","2","3"]) // The argument is an array of ["String": Swift.String] test(Set<String>()) // The argument is not an array test([1: 2,3: 4]) // The argument is not an array test((1,3)) // The argument is not an array test(3) // The argument is not an array test("3") // The argument is not an array test(NSObject()) // The argument is not an array test(NSArray(array:[1,3])) // The argument is an array of ["_SwiftTypePreservingNSNumber": _SwiftTypePreservingNSNumber]
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 [email protected] 举报,一经查实,本站将立刻删除。