Python的多繼承最好是當C#或者Java裡面的介面使用，這樣結構不會混亂( 特殊情況除外)

來個例子：

class Animal(object):
    pass

class Flyable(object):
    """飛的方法"""
    pass

class Runable(object):
    """跑的方法"""
    pass

class Dog(Animal, Runable):
    pass

class Cat(Animal, Runable):
    pass

class Bird(Animal, Flyable
 
):
    pass

class Dack(Animal, Runable, Flyable):
    """鴨子會飛也會跑"""
    pass

和C#一樣，Python的 父類建構函式不會被繼承

其實從資源角度也不應該被繼承，如果有1w個子類，那每個子類裡面都有一個父類方法，想想這是多麼浪費的一件事情？

2.3.C#繼承 ¶

下課後，小明認真思考總結，然後對照Python寫下了C#版的繼承：

定義一個人類

public class Person
{
    public string Name { get; set; }
    public
 
 ushort Age { get; set; }

    public Person(string name, ushort age)
    {
        this.Name = name;
        this.Age = age;
    }
    public void Hi()//People
    {
        Console.WriteLine("Name: " + this.Name + " Age: " + this.Age);
    }
    public virtual void Show()//People
    {
        Console
 
.WriteLine("Name: " + this.Name + " Age: " + this.Age);
    }
}

定義一個學生類

public class Student : Person
{
    #region 屬性
    /// <summary>
    /// 學校
    /// </summary>
    public string School { get; set; }
    /// <summary>
    /// 班級
    /// </summary>
    public string StrClass { get; set; }
    /// <summary>
    /// 學號
    /// </summary>
    public string StrNum { get; set; }
    #endregion

    #region 建構函式
    /// <summary>
    /// 呼叫父類建構函式
    /// </summary>
    /// <param name="name"></param>
    /// <param name="age"></param>
    public Student(string name, ushort age) : base(name, age)
    {

    }
    public Student(string name, ushort age, string school, string strClass, string strNum) : this(name, age)
    {
        this.School = school;
        this.StrClass = strClass;
        this.StrNum = strNum;
    } 
    #endregion

    /// <summary>
    /// new-隱藏
    /// </summary>
    public new void Hi()//Student
    {
        Console.WriteLine("Name: " + this.Name + " Age: " + this.Age + " School: " + this.School + " strClass: " + this.StrClass + " strNum: " + this.StrNum);
    }
    /// <summary>
    /// override-覆蓋
    /// </summary>
    public override void Show()//Student
    {
        Console.WriteLine("Name: " + this.Name + " Age: " + this.Age + " School: " + this.School + " strClass: " + this.StrClass + " strNum: " + this.StrNum);
    }
}

呼叫一下：

Person p = new Student("app", 10, "北京大學", "001", "01001");
p.Hi(); p.Show();

Console.WriteLine();

Student s = p as Student;
s.Hi(); s.Show();

結果:

Name: app Age: 10
Name: app Age: 10 School: 北京大學 strClass: 001 strNum: 01001
Name: app Age: 10 School: 北京大學 strClass: 001 strNum: 01001
Name: app Age: 10 School: 北京大學 strClass: 001 strNum: 01001

2.4C#介面的多實現 ¶

定義兩個介面：

public interface IRun
{
    //什麼都不用加
    void Run();
}

public interface IEat
{
    void Eat();
}

定義一個Dog類來實現兩個介面，這樣dog就有了run和eat的方法了

var dog = new Dog();
dog.Eat();
dog.Run();

結果：

狗狗吃
狗狗跑

3 多型 ¶

3.1.Python ¶

說多型之前說說型別判斷，以前我們用 type() or isinstance()

判斷一個變數和另一個變數是否是同一個型別==> type(a)==type(b)

判斷一個變數是否是某個型別==> type(a)==A or isinstance(a,A)