如何简化Swift数组初始化

Question

这是参考。给出如下语句：

let fooPaths: [WritableKeyPathApplicator<Foo>] = [WritableKeyPathApplicator(\Foo.bar), WritableKeyPathApplicator(\Foo.baz)]

是否有 init 或其他可以完成的操作，以便以下（或类似的）也可以工作？

let fooPaths: [WritableKeyPathApplicator<Foo>] = [\Foo.bar, \Foo.baz]

原来的说法是打字太多了！我的 "preferred" 方法当前给出错误：

error: cannot convert value of type 'WritableKeyPath<Foo, String>' to expected element type 'WritableKeyPathApplicator<Foo>'

Answer 1

不需要类型：

let fooPaths = [WritableKeyPathApplicator(\Foo.bar), WritableKeyPathApplicator(\Foo.baz)]

不需要第二个Foo。

let fooPaths = [WritableKeyPathApplicator(\Foo.bar), WritableKeyPathApplicator(\.baz)]

也是第一个，如果你提供了类型：

let fooPaths: [WritableKeyPathApplicator<Foo>] = [WritableKeyPathApplicator(\.bar),
                                                  WritableKeyPathApplicator(\.baz)]

如果主要关心的是打字，请添加本地类型别名：

typealias WKPA<T> = WritableKeyPathApplicator<T>
let fooPaths: [WKPA<Foo>] = [WKPA(\.bar),
                             WKPA(\.baz)]

如何简化Swift数组初始化

How to simplify Swift array initialization

arrays

swift

keypaths