Python中类的__init__继承

概念：

　定义父类

In [10]: class Person:

   ....:     def __init__(self,name,age,sex):

   ....:         self.name = name

   ....:         self.age = age

   ....:         self.sex = sex

   ....:     def get_name(self):

   ....:         print('name:',self.name)

   ....:

In [11]: Bob = Person('Bob',18,'男')

In [12]: Bob.get_name()

name: Bob

【1】子类不重写__init__，实例化子类时，会自动调用父类定义的__init__

In [13]: class Person_child(Person):

   ....:     def get_name(self):

   ....:         print('name:',self.name)

   ....:         

In [14]: child = Person_child('baby',2,'男')

In [15]: child.get_name()

name: baby

【2】另一种的验证方式

class Person:

    def __init__(self,name,age):

        self.name = 'Bob'

        self.age = 18

    def get_name(self):

        print('name:',self.name)

class Student(Person):

    def get_name(self):

        print('name:',self.name)    

Kevin = Student('Kevin',12)

print('-------------------------')

print(Kevin.name)

print(Kevin.age)

print('-------------------------')

output

-------------------------

Bob

18

-------------------------

【3】但重写了__init__时，实例化子类，就不会调用父类已经定义的__init__

In [17]: class Person_child(Person):

   ....:     def __init__(self,name,age,sex):

   ....:         self.name = name

   ....:         self.age = age

   ....:         self.sex = sex

   ....:     def get_name(self):

   ....:         print('child_name:',self.name)

   ....:         

In [18]: K = Person_child('Kevin',16,'男')

In [19]: K.get_name()

child_name: Kevin

【4】为了能使用或扩展父类的行为，最好显示调用父类的__init__方法

class Person:

    def __init__(self,name,age):

        self.name = 'Bob'

        self.age = 18

    def get_name(self):

        print('name:',self.name)

class Student(Person):

    def __init__(self,name,age,sex):

        super(Student,self).__init__(name,age)

        self.sex = sex

    def get_detail(self):

        print('详细信息：',self.name,'---',self.age,'---',self.sex)

Kevin = Student('Kevin',12,'男')

print('-------------------------')

print(Kevin.name)

print(Kevin.age)

print(Kevin.sex)

print(Kevin.get_detail())

print('-------------------------')

# output

-------------------------

Bob

18

男

详细信息： Bob --- 18 --- 男

None

-------------------------

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