如何从特定键对数组进行排序？

Question

目前，我有一个数组声明为：

let VitamineARetinol = "VitamineARetinol"
let VitamineABetacarotene = "VitamineABetacarotene"
let VitamineC = "VitamineC"
let VitamineD = "VitamineD"
let Calories = "Calories"

typealias ListOfAliment = [String: [String: Double]]


let Data: ListOfAliment = [
    "Orange": [VitamineARetinol: 0.5, VitamineC: 0.3, VitamineD: 0.98, Calories: 100],
    "Pomme": [VitamineARetinol: 0.2, VitamineC: 0.2, VitamineD: 0.38, Calories: 120],
    "Poire": [VitamineARetinol: 0.1, VitamineC: 0.7, VitamineD: 0.58, Calories: 140],
    "Laitue": [VitamineARetinol: 0.3, VitamineC: 0.1, VitamineD: 0.92, Calories: 105],
    "Banane": [VitamineARetinol: 0.7, VitamineC: 0.01, VitamineD: 0.63, Calories: 122]
]

var ListOfAlimentClassed = Data

我需要从卡路里键对其进行排序，同时保留所有数组数据，如下所示：

ListOfAlimentClassed = [
"Orange": [VitamineARetinol: 0.5, VitamineC: 0.3, VitamineD: 0.98, Calories: 100],
"Laitue": [VitamineARetinol: 0.3, VitamineC: 0.1, VitamineD: 0.92, Calories: 105],
"Pomme": [VitamineARetinol: 0.2, VitamineC: 0.2, VitamineD: 0.38, Calories: 120],
"Banane": [VitamineARetinol: 0.7, VitamineC: 0.01, VitamineD: 0.63, Calories: 122],
"Poire": [VitamineARetinol: 0.1, VitamineC: 0.7, VitamineD: 0.58, Calories: 140]
]

我怎样才能在 Swift 中有效地做到这一点？请帮忙！

Answer 1

let sorted = ListOfAlimentClassed.sorted { (([=10=].1[Calories] as? Double) ?? 0) < ((.1[Calories] as? Double) ?? 0) }

Answer 2

为您的数据创建一个结构并改为使用数组

struct Aliment {
    let name: String
    let vitamineARetinol: Double
    let vitaminC: Double
    let vitaminD: Double
    let calories: Double
}

var array = [
    Aliment(name: "Orange", vitamineARetinol: 0.5, vitaminC: 0.3, vitaminD: 0.98, calories: 100),
    Aliment(name: "Pomme", vitamineARetinol: 0.2, vitaminC: 0.2, vitaminD: 0.38, calories: 120),
]

array.sort(by: { [=10=].calories < .calories })

阅读 Swift Programming Language 书中关于结构的更多信息

如何从特定键对数组进行排序？

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