SwiftUI 中使用的反斜杠 (\) 是什么? [英] What is the backslash(\) used for in SwiftUI?

问题描述

在名为组合复杂接口"的 SwiftUI 的 Apple 教程中，该教程使用了一个反斜杠，它似乎不是字符串插值或转义字符.这是一行:

In the Apple tutorial for SwiftUI called "Composing Complex Interfaces", the tutorial uses a backslash that doesn't appear to be string interpolation or an escape character. This is the line:

ForEach(categories.keys.sorted().identified(by: \.self))

这个反斜杠的目的是什么?

What is the purpose of this backslash?

下面是包含它的整个结构.

Below is the entire Struct that contains it.

struct CategoryHome: View {
    var categories: [String: [Landmark]] {
        .init(
            grouping: landmarkData,
            by: { $0.category.rawValue }
        )
    }

    var body: some View {
        NavigationView {
            List {
                ForEach(categories.keys.sorted().identified(by: \.self)) { key in
                    Text(key)
                }
            }
            .navigationBarTitle(Text("Featured"))
        }
    }
}

推荐答案

\.self 这是苹果添加的身份密钥路径:

\.self it's a identity keypath that apple added for:

添加引用身份密钥路径的能力，该路径引用它所应用到的整个输入值.

Add the ability to reference the identity key path, which refers to the entire input value it is applied to.

提案中的更多信息.

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