在Swift中将一本字典与另一本字典相乘

问题描述

目前，我有一个嵌套的字典声明为：

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: 160],"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],]

我需要在以下字典中将每个值除以其对应的值：

let reference: ListOfAliment = [
    "reference": [VitamineARetinol: 0.2,VitamineD: 0.4],]

最后，我应该得到一个食物字典，其中每种食物的所有值都被字典参考中的相应值除以 拜托，有人可以帮我吗！

解决方法

鉴于我在previous question中的回答，您可以简单地将值数组映射到新数组中

let adjustedData = array
    .map { Aliment(name: $0.name,vitamineARetinol: $0.vitamineARetinol / 0.2,vitaminC: $0.vitaminC / 0.1,vitaminD: $0.vitaminD / 0.4,calories: $0.calories)}

,

您绝对应该为内部词典创建一个结构。因为这样您可以在结构中添加dividedBy方法来进行除法。我不确定将一种食物除以另一种食物是否有意义。如果是这样，您可以将divideBy方法更改为接受另一个Aliment。

struct Aliment {
    let vitaminARetinol: Double
    let vitaminC: Double
    let vitaminD: Double
    let calories: Double
    
    func dividedBy(vitaminARetinolFactor: Double,vitaminCFactor: Double,vitaminDFactor: Double,caloriesFactor: Double) -> Aliment {
        Aliment(vitaminARetinol: vitaminARetinol / vitaminARetinolFactor,vitaminC: vitaminC / vitaminCFactor,vitaminD: vitaminD / vitaminDFactor,calories: calories / caloriesFactor)
    }
}
typealias ListOfAliment = [String: Aliment]
let data: ListOfAliment = [
    "Orange": Aliment(vitaminARetinol: 0.5,vitaminC: 0.3,vitaminD: 0.98,calories: 160),"Pomme": Aliment(vitaminARetinol: 0.2,vitaminC: 0.2,vitaminD: 0.38,calories: 120),"Poire": Aliment(vitaminARetinol: 0.1,vitaminC: 0.7,vitaminD: 0.58,calories: 140),"Laitue": Aliment(vitaminARetinol: 0.3,vitaminC: 0.1,vitaminD: 0.92,calories: 105),"Banane": Aliment(vitaminARetinol: 0.7,vitaminC: 0.01,vitaminD: 0.63,calories: 122),]

要转换字典，可以使用mapValues：

let referenceNumbers = reference["reference"]!
let newData = data.mapValues { 
    $0.dividedBy(vitaminARetinolFactor: referenceNumbers[VitamineARetinol]!,vitaminCFactor: referenceNumbers[VitamineC]!,vitaminDFactor: referenceNumbers[VitamineD]!,caloriesFactor: referenceNumbers[Calories]!) 
}

同样，如果有意义的是将一种食物分割为另一种，则您也可以将引用设为Aliment对象，并将其传递给divideBy。