一個變量，一個類和兩個相同功能的函數迅速

Question

我已經在谷歌上搜索了這個答案很長時間，直到我在堆棧溢出時創建了一個帳戶來問這個問題。

您如何編程一個變量以保存其中包含某個變量的類，然后兩次調用同一函數？ 代碼說明：

class Persons {

var oldName = ""
var oldAge = 0
var oldGender = ""
var name = ""
var age = 0
var gender = ""

func create(_ name:String, _ age:Int, _ gender:String) -> String {

    if(age > 100) {
        print("Can't create a person with an age that is over 100!")

        return "Not created!"
    }

    if(gender == "Boy" || gender == "Girl") {

    }
    else {
        print("Gender has to be a girl or a boy!")

        return "Not created!"
    }
    self.name = name
    self.age = age
    self.gender = gender

    self.oldName = name
    self.oldAge = age
    self.oldGender = gender

    print("You just created a \(gender) called: '\(name)' with the age of: '\(age)'!")

    return "Created!"
}

func modify(_ targetName:String, _ newName:String, _ newAge:Int, _ newGender:String) -> String {

    if(age > 100) {
        print("Can't modify a person with an age that is over 100!")
        return "Not modified!"
    }

    if(gender == "Boy" || gender == "Girl") {

    }
    else {
        print("Gender has to be a girl or a boy!")
        return "Not modified!"
    }

    if(targetName != "" && targetName == self.name) {
        self.name = newName
        self.age = newAge
        self.gender = newGender

        print("You just changed \(oldName)'s gender from: \(oldGender) to: \(gender), \(oldName)'s name from: \(oldName) to: \(name) and \(oldName)'s age from: \(oldAge) to: \(age)!")
    }
    else {
        print("Please enter a valid target name or create one!")
    }

    return "Modified!"
}

func delete(_ targetName:String) -> String {

    if(name != "" && targetName == self.name) {
        print("Deleted: \(name)!")
    }
    else {
        print("Please enter a valid target name or create one!")
    }

    return "Deleted!"
}

}

var p = Persons()
p.create("Isak", 11, "Boy")
p.create("Sanne", 7, "Girl") // Here I create another person
p.delete("Isak") // But if I say delete 'Isak' it does not delete him because I created 'Sanne' above!

/*
It would work like this

p.create("Isak", 11, "Boy")
p.delete("Isak")
p.create("Sanne", 7, "Girl")
*/

請幫忙。 我花了很長時間才找到答案。 如果您需要更多詳細信息，請回復，我將嘗試解釋更多內容。

Answer 1

這里的問題是您正在使用Person的單個實例。 在執行操作時：

p.create("Isak", 11, "Boy")
p.create("Sanne", 7, "Girl") // Here I create another person

盡管您只是在編輯Person類的p實例的屬性，但您並未創建其他人。 因此，當您刪除Isak時：

p.delete("Isak")

現在還沒有Isak，他已改名為Sanne。

要解決此問題，您應該創建兩個單獨的Person實例：

var p1 = Persons()
var p2 = Persons()
p1.create("Isak", 11, "Boy")
p2.create("Sanne", 7, "Girl") // Here I create another instance of person
p1.delete("Isak")

在這種狀態下，您有兩個人：您剛剛刪除的Sanne和Isak，並且Sanne仍然存在並且可以訪問。

如果要使用單個實例來容納所有人員，請使用以下命令：

class Person {
var oldName = ""
var oldAge = 0
var oldGender = ""
var name = ""
var age = 0
var gender = ""

func create(_ name:String, _ age:Int, _ gender:String) -> String {

    if(age > 100) {
        print("Can't create a person with an age that is over 100!")

        return "Not created!"
    }

    if(gender == "Boy" || gender == "Girl") {

    }
    else {
        print("Gender has to be a girl or a boy!")

        return "Not created!"
    }
    self.name = name
    self.age = age
    self.gender = gender

    self.oldName = name
    self.oldAge = age
    self.oldGender = gender

    print("You just created a \(gender) called: '\(name)' with the age of: '\(age)'!")

    return "Created!"
}

func modify(_ targetName:String, _ newName:String, _ newAge:Int, _ newGender:String) -> String {

    if(age > 100) {
        print("Can't modify a person with an age that is over 100!")
        return "Not modified!"
    }

    if(gender == "Boy" || gender == "Girl") {

    }
    else {
        print("Gender has to be a girl or a boy!")
        return "Not modified!"
    }

    if(targetName != "" && targetName == self.name) {
        self.name = newName
        self.age = newAge
        self.gender = newGender

        print("You just changed \(oldName)'s gender from: \(oldGender) to: \(gender), \(oldName)'s name from: \(oldName) to: \(name) and \(oldName)'s age from: \(oldAge) to: \(age)!")
    }
    else {
        print("Please enter a valid target name or create one!")
    }

    return "Modified!"
}

func delete() -> String {
    return "Deleted!"
}
}

class Persons {
var personsDictionary = [String: Person]()
}

var persons = Persons()
var p1 = Person()
var p2 = Person()

p1.create("Isak", 11, "Boy")
p2.create("Sanne", 7, "Girl")

persons.personsDictionary[p1.name] = p1
persons.personsDictionary[p2.name] = p2

persons.personsDictionary["Isak"]?.delete()

在這里，我們有一個Person類（您在問題中定義的一個類，但具有稍微改變的delete()方法）和Persons類，它們的字典為[String : Person] 。 詞典的關鍵是您這個人的名字，值是這個人。

當我們創建一個人員實例時，我們將其存儲在personsDictionary然后我們可以通過人員名稱訪問該詞典中的每個人，並且將返回一個Optional，我們可以在該Optional上調用所有定義的方法。

Answer 2

您還試圖將模型對象用作存儲庫。

您只需要一個簡單的模型，對於一個簡單的模型，最好使用結構。 這也為您免費提供初始化程序

struct Person {
    var name = ""
    var age = 0
    var gender = ""
}

注意：最好將枚舉用於性別...

enum Gender {
    case male, female
}

struct Person {
    var name = ""
    var age = 0
    var gender: Gender = .male
}

然后只需使用數組來管理列表

let simon = Person(name: "Simon", age: 20, gender: .male)
let isak = Person(name: "Isak", age: 11, gender: .male)

var people = [simon, isak]

print(people.count) // output: 2
people.remove(isak)
print(people.count) // output: 1

let sanne = Person(name: "Sanne", age: 7, gender: .female)
people.append(sanne)

我建議您通讀文檔實例化，並且數組是非常基本的。 至少閱讀有關類，結構，實例化和數組的信息。

Answer 3

這是我將如何做的開始...

首先，該類負責處理所有事情：

class Person {
    /// An enum for gender so that you can only ever use the permissable values.
    public enum Gender {
        case male
        case female
    }

    /// An enum for the results so there are defined values to check (you could add more specific errors).
    public enum Result {
        case success
        case failed(_: String)
    }

    /// A structure to hold the details of each person.
    struct PersonData {
        var name: String
        var age: UInt
        var gender: Gender
    }

    /// The internal list of people.
    private var personList: [String: PersonData] = [:]

    /// A function to create a person.
    func create(_ name: String, _ age: UInt, _ gender: Gender) -> Result {
        guard personList[name] == nil else {
            print ("Person already created!")

            return .failed("Person already created!")
        }

        guard age <= 100 else {
            print("Can't create a person with an age that is over 100!")

            return .failed("Cannot have age over 100!")
        }

        let person = PersonData(name: name, age: age, gender: gender)
        personList[name] = person

        print("You just created a \(gender) called: '\(name)' with the age of: '\(age)'!")

        return .success
    }

    /// A function to modify a persons details in the list.
    func modify(_ targetName: String, _ newName: String, _ newAge: UInt, _ newGender: Gender) -> Result {
        guard let person = personList[targetName] else {
            print ("Person not found in list!")

            return .failed("Person not found!")
        }

        guard personList[newName] == nil else {
            print ("Person already exists in list!")

            return .failed("Person already exist in the list!")
        }

        if newAge > 100 {
            print("Can't modify a person with an age that is over 100!")

            return .failed("Cannot modify a person with an ager over 100!")
        }

        let oldName = person.name
        let oldAge = person.age
        let oldGender = person.gender

        if targetName != newName {
            personList.removeValue(forKey: targetName)
        }
        personList[newName] = PersonData(name: newName, age: newAge, gender: newGender)

        print("You just changed \(oldName)'s gender from: \(oldGender) to: \(person.gender), \(oldName)'s name from: \(oldName) to: \(person.name) and \(oldName)'s age from: \(oldAge) to: \(person.age)!")

        return .success
    }

    /// A function to delete a person from the list.
    func delete(_ targetName:String) -> Result {
        guard let _ = personList[targetName] else {
            print ("Person not found in list!")

            return .failed("Person not found in list!")
        }

        personList.removeValue(forKey: targetName)

        print("Deleted: \(targetName)!")

        return .success
    }

    /// A test function to print out the current list of people.
    func printList() {
        for (name, person) in personList {
            print ("\(name) is \(person.gender) and age \(person.age)")
        }
    }

    /// Bonus to allow you to get a persons full details using something like person[name].
    subscript(name: String) -> PersonData? {
        return personList[name]
    }
}

現在，您可以使用它：

let people = Person()

// Create Isak.
var result = people.create("Isak", 11, .male)

// Here is how to detail with the results.
switch result {
case .success:
    // Do something when successfully created.
    print ("Result = Success")
case .failed(let reason):
    // Do something when failed to create.
    print ("Result = \(reason)")
}

// Create Sanne
result = people.create("Sanne", 7, .female)

// Print the list to check they are in there.
people.printList()

// Delete Isak from the list.
result = people.delete("Isak")

// Change Sanne's name to New Sanne and age to 8.
result = people.modify("Sanne", "New Sanne", 8, .female)

// Print the list to check what's in there.
people.printList()

// Bonus showing how to get a persons full details.
if let personData = people["New Sanne"] {
    print ("\(personData.name) is \(personData.gender) and age \(personData.age)")
} else {
    print ("Not Found!")
}

結果應為：

You just created a male called: 'Isak' with the age of: '11'!
Result = Success
You just created a female called: 'Sanne' with the age of: '7'!
Sanne is female and age 7
Isak is male and age 11
Deleted: Isak!
You just changed Sanne's gender from: female to: female, Sanne's name from: Sanne to: Sanne and Sanne's age from: 7 to: 7!
New Sanne is female and age 8
New Sanne is female and age 8

我也可能會更進一步，但這應該足以讓您入門。

（希望這些評論能夠說明發生了什么，但是如果不能隨意詢問的話）