Swift：错误：在隐式展开可选值时意外发现 nil

Posted 2023-03-28

【中文标题】Swift：错误：在隐式展开可选值时意外发现 nil

【英文标题】：Swift: error: Unexpectedly found nil while implicitly unwrapping an Optional value

【发布时间】：2020-12-28 05:49:41

【问题描述】：

我收到此错误代码：

错误：执行被中断，原因：EXC_BAD_INSTRUCTION （代码=EXC_I386_INVOP，子代码=0x0）。该过程已留在 中断点，使用“thread return -x”返回 表达式求值前的状态。

PlayGround 说：

致命错误：在隐式展开时意外发现 nil 可选值：文件 BilanDico-04.playground，第 137 行

这是我的代码：

import Foundation
import UIKit

let TableauDesBesoinsQuotidienEnVitaminesretenues : [String : Float] = [
    "aRetinol"      : 800,
    "aBetacarotene" : 2100,
    "vitamineC"     : 80,
    "vitamineB1"    : 1.1,
    "calcium"       : 800,
    "omega3"        : 2
]

let TableauDesVitaminesRetenuesPourObjectifs : [String] = [
    "aRetinol",
    "aBetacarotene",
    "vitamineC",
    "vitamineB1",
    "calcium",
    "omega3"
]

class AlimentObject 
    var id = UUID().uuidString
    var nomAliment = "Nouvel aliment"
    var poids : Float = 100
    var calories : Float = 0
    var proteines : Float = 0
    var lipides : Float = 0
    var glucides : Float = 0
    var aRetinol : Float = 0
    var aBetacarotene : Float = 0
    var vitamineC : Float = 0
    var vitamineB1 : Float = 0
    var calcium : Float = 0
    var omega3 : Float = 0
    var comments : String = ""
    var premierBooleen: Bool
    var optimize: Bool
    
    init(nomAliment: String, poids: Float, calories: Float, proteines: Float, lipides: Float, glucides: Float, aRetinol: Float, aBetacarotene: Float, vitamineC: Float, vitamineB1: Float, calcium: Float, omega3: Float, comments:String, premierBooleen: Bool, optimize: Bool) 
        
        self.nomAliment = nomAliment
        self.poids = poids
        self.calories = calories
        self.proteines = proteines
        self.lipides = lipides
        self.glucides = glucides
        self.aRetinol = aRetinol
        self.aBetacarotene = aBetacarotene
        self.vitamineC = vitamineC
        self.vitamineB1 = vitamineB1
        self.calcium = calcium
        self.omega3 = omega3
        self.comments = comments
        self.premierBooleen = false
        self.optimize = false
    
    
    convenience init() 
        self.init(nomAliment: "Aliment intialisé à zéro", poids: 100, calories: 0, proteines: 0, lipides: 0, glucides: 0, aRetinol: 0, aBetacarotene: 0, vitamineC: 0, vitamineB1: 0, calcium: 0, omega3: 0, comments: "", premierBooleen: false, optimize: false)
    


class Donnees 
    
    static var AlimentListWithSections = [[AlimentObject]]()
    
    static let list1 = [
        AlimentObject(nomAliment: "Blanc de poulet", poids: 100, calories: 108, proteines: 24, lipides: 1, glucides: 0, aRetinol: 8, aBetacarotene: 0, vitamineC: 0, vitamineB1: 0.08, calcium: 8, omega3: 0.03, comments: "sdsdsdsdsd sdsddsdsd", premierBooleen: false, optimize: false),
        AlimentObject(nomAliment: "Avocat", poids: 100, calories: 147, proteines: 1.76, lipides: 13.80, glucides: 1.57, aRetinol: 0, aBetacarotene: 55, vitamineC: 5.49, vitamineB1: 0.05, calcium: 11.2, omega3: 0.08, comments: "aaaaaaaaa sdsddsdsd", premierBooleen: false, optimize: false),
        AlimentObject(nomAliment: "Amandes", poids: 100, calories: 634, proteines: 21, lipides: 53, glucides: 8, aRetinol: 8, aBetacarotene: 1, vitamineC: 0.8, vitamineB1: 0.18, calcium: 248, omega3: 0.06, comments: "fffffff sdsddsdsd", premierBooleen: false, optimize: false)
    ]
    
    static let list2 = [
        AlimentObject(nomAliment: "Poivron Jaune", poids: 100, calories: 29.2, proteines: 1, lipides: 5.42, glucides: 0.21, aRetinol: 0, aBetacarotene: 120, vitamineC: 184, vitamineB1: 0.03, calcium: 11, omega3: 0.02, comments: "lllllllssss", premierBooleen: false, optimize: false),
        AlimentObject(nomAliment: "Saumon cru", poids: 100, calories: 192, proteines: 20.5, lipides: 12.2, glucides: 0, aRetinol: 8, aBetacarotene: 0, vitamineC: 1.6, vitamineB1: 0.21, calcium: 8, omega3: 1.79, comments: "eeeeeeee", premierBooleen: false, optimize: false)
    ]
    
    static let list3 : [AlimentObject] = [
        AlimentObject(nomAliment: "Avocat", poids: 100, calories: 147, proteines: 1.76, lipides: 13.80, glucides: 1.57, aRetinol: 0, aBetacarotene: 55, vitamineC: 5.49, vitamineB1: 0.05, calcium: 11.2, omega3: 0.08, comments: "aaaaaaaaa sdsddsdsd", premierBooleen: false, optimize: false),
    ]
    
    static let list4 : [AlimentObject] = [
        AlimentObject(nomAliment: "Amandes", poids: 100, calories: 634, proteines: 21, lipides: 53, glucides: 8, aRetinol: 8, aBetacarotene: 1, vitamineC: 0.8, vitamineB1: 0.18, calcium: 248, omega3: 0.06, comments: "fffffff sdsddsdsd", premierBooleen: false, optimize: false)
    ]
    
    static let list5 : [AlimentObject] = []
    static let listVide : [AlimentObject] = []
    static let listDuJour = [list1, list2, list3, list4, list5]


class AlimentFunctions 
    // sommer des Float d'une macro du Menu et sortir un Float
    static func sumDUneMacroDuMenuToFloat(NameList list: [[AlimentObject]], macro: String) -> Float 
        var totalsection: Float = 0.0
        var total: Float = 0.0
        
        list.forEach 
            totalsection = 0
            $0.forEach( (aliment) in
                if let value = Mirror(reflecting: aliment).children.first(where:  $0.label == macro )?.value as? Float 
                    totalsection += value
                
            )
            total += totalsection
        
        return total
    



class TotauxVitamineMineraux 
    static func DicoDesTotauxPaffonesEtNonPlaffonesDesVitamines(with menu: [[AlimentObject]], tableauDesNomsDesMacrosRetenues: [String], tableauDesValeursDesMacros: [String: Float]) -> [String: (Float, Float, Float, Float, Float)] 
        var dico: [String: (Float, Float, Float, Float, Float)]!
        for macro in tableauDesNomsDesMacrosRetenues 
            let premier = tableauDesValeursDesMacros[macro]!
            let second = AlimentFunctions.sumDUneMacroDuMenuToFloat(NameList: menu, macro: macro)
            let troisieme = second / tableauDesValeursDesMacros[macro]! * 100
            var quatrieme = second
            if second > 100  quatrieme = 100 
            if second <= 100  quatrieme = second 
            let cinquieme = quatrieme / tableauDesValeursDesMacros[macro]! * 100
            dico[macro] = (premier, second, troisieme, quatrieme, cinquieme)
        
        return dico
    


let dico = TotauxVitamineMineraux.DicoDesTotauxPaffonesEtNonPlaffonesDesVitamines(with: Donnees.listDuJour, tableauDesNomsDesMacrosRetenues: TableauDesVitaminesRetenuesPourObjectifs, tableauDesValeursDesMacros: TableauDesBesoinsQuotidienEnVitaminesretenues)

print(dico)

错误在这一行： dico[macro] = (premier, second, troisieme, quatrieme, cinquieme)

【问题讨论】：

代码中的第 137 行在哪里（发生错误的位置）？

在这一行：dico[macro] = (premier, second, troisieme, quatrieme, cinquieme)

【参考方案1】：

var dico: [String: (Float, Float, Float, Float, Float)]! 保证该字典将存在，但没有创建它。然后，当您尝试将您说不会为 nil 的内容放入 nil 字典中时，程序会崩溃。

【讨论】：

那我该怎么办？

在尝试将内容放入字典之前创建字典。