arrays - 如何按键对 Dictionary 进行排序，其中值是 Swift 4 中的对象数组？

Question

我有一个字典，其中包含 String 键和 Objects 数组作为值。使用 append 方法将这些值从已排序的对象数组添加到字典中。这些值根据对象属性的首字母分类为键。但返回未排序的字典。

字典被声明为:

var namesDic = [String: [Name]]()

var filteredNames = [String: [Name]]()

遍历数组并追加到字典中:

for name in names {
        let letterIndex = name.getName().index(name.getName().startIndex, offsetBy: 0)

        let letter = name.getName()[letterIndex]

        if namesDic[String(letter)] != nil {
            namesDic[String(letter)]?.append(name)
        } else {
            namesDic[String(letter)] = [name]
        }
    }
    filteredNames = namesDic

}

名称结构:

struct Name {
    var id: Int!
    var name: String!
    var native: String!
    var meaning: String!
    var origin: String!
    var isFavorite: Bool
    var gender: String!

    init(id: Int, name: String, native: String, meaning: String, origin: String, isFavorite: Int, gender: String) {
        self.id = id
        self.name = name
        self.native = native
        self.meaning = meaning
        self.origin = origin
        if isFavorite == 0 {
            self.isFavorite = false
        } else { self.isFavorite = true }
        self.gender = gender
    }
}

我在调试中发现，当它们附加到字典时，它们是未排序的。我知道 Swift Dictionary 上的排序不起作用，但我想要解决方法来按键对 Dictionary 进行排序以将其传递给 TableView。

我在这里经历了很多问题/答案，但它们都是针对 [String: String] 而不是 Array of Objects。

Answer 1

struct Name: CustomStringConvertible {
    let id: Int
    let name: String
    let native: String
    let meaning: String
    let origin: String
    let isFavorite: Bool
    let gender: String
    var description: String {
        return "Id: " + String(id) + " - Name: " + name 
    }
}

let name1 = Name(id: 1, name: "Tim Cook", native: "native", meaning: "meaning", origin: "origin", isFavorite: true, gender: "Male")
let name2 = Name(id: 2, name: "Steve Jobs", native: "native", meaning: "meaning", origin: "origin", isFavorite: true, gender: "Male")
let name3 = Name(id: 3, name: "Tiger Woods", native: "native", meaning: "meaning", origin: "origin", isFavorite: true, gender: "Male")
let name4 = Name(id: 4, name: "Socrates", native: "native", meaning: "meaning", origin: "origin", isFavorite: true, gender: "Male")

let names = [name1, name2, name3, name4]


let dictionary = names.sorted(by: {$0.name < $1.name }).reduce(into: [String: [Name]]()) { result, element in
    // make sure there is at least one letter in your string else return
    guard let first = element.name.first else { return }
    // create a string with that initial
    let initial = String(first)
    // initialize an array with one element or add another element to the existing value
    result[initial, default: []].append(element)
}

---

let sorted = dictionary.sorted {$0.key < $1.key}
print(sorted)   // "[(key: "S", value: [Id: 4 - Name: Socrates, Id: 2 - Name: Steve Jobs]), (key: "T", value: [Id: 3 - Name: Tiger Woods, Id: 1 - Name: Tim Cook])]\n"