我想检查泛型类类型是否是数组:
func test<T>() -> Wrapper<T> {
let isArray = T.self is Array<Any>
...
}
但它警告
Cast from 'T.type' to unrelated type 'Array' always fails
我该如何解决这个问题?
添加:我已经将我的代码上传到 Gist。 https://gist.github.com/nallwhy/6dca541a2d1d468e0be03c97add384de
我想做的是根据它是一个模型数组还是一个模型来解析 json 响应。
最佳答案
正如评论员@Holex 所说,您可以使用Any
。将它与 Mirror
结合起来,例如,您可以执行如下操作:
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, 2, "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, 2, 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, 2, 3])) // The argument is an array of ["_SwiftTypePreservingNSNumber": _SwiftTypePreservingNSNumber]
关于swift - 如何检查泛型类类型是数组?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41518371/