检查元素错误的索引

Question

我想检查数组中元素的索引：

var arr: [Any] = ["st","er","gh", 2, 5,"jk", 78 ]
print(arr.index(of: 2))

但是我收到了错误：

error: cannot invoke 'index' with an argument list of type '(of: Any)'
note: expected an argument list of type '(of: Self.Element)'

为什么控制台会抛出这个以及如何修复它？

Answer 1

为了使用索引（of :)，必须采用Equatable协议

试试这段代码

   var arr: [Any] = ["st","er","gh", 2, 5,"jk", 78 ]
        print(arr.index(where: { (item) -> Bool in
            (item as? Int ) == 2
        }))

Answer 2

在异构数组中，您必须使用index(where API并检查元素的类型：

let arr: [Any] = ["st","er","gh", 2, 5,"jk", 78 ]
if let index = arr.index(where: { $0 as? Int == 2 }) {
   print(index)
}