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python中super的用法

super()方法的漂亮之處在於,你不需要在定義子類構造器時,明確的指定子類的基類並顯式的呼叫,即不需要明確的提供父類,這樣做的好處就是,如果你改變了繼承的父類,你只需要修改一行程式碼(class程式碼行),而不需要在大量程式碼中去查詢那個要修改的基類。另外一方面程式碼的可移植性和重用性也更高。
1、單繼承

class FooParent(object):
    def __init__(self):
        self.parent = 'I\'m the parent.'
        print ('Parent')
    
    def bar(self,message):
        print (message,'from Parent')
 
class FooChild(FooParent):
    def __init__(self):
        super(FooChild,self).__init__()
        print ('Child')
        
    def bar(self,message):
        super(FooChild, self).bar(message)
        print ('Child bar fuction')
        print (self.parent)
 
if __name__ == '__main__':
    fooChild = FooChild()
    fooChild.bar('HelloWorld')

答案是:

Parent
Child
HelloWorld from Parent
Child bar fuction
I'm the parent.

2、多繼承

class A:
    def __init__(self):
        #print(super())
        print("Enter A")
        print("Leave A")

class B(A):
    def __init__(self):
        print("Enter B")
        #print(super())
        super().__init__()
        print("Leave B")

# single = B()
# print(B.mro())
class C(A):
    def __init__(self):
        print("Enter C")
        print(super())
        super().__init__()
        print("Leave C")


class D(B,C):
    def __init__(self):
        print("Enter D")
        #print(super())
        super().__init__()
        print("Leave D")

D()
print(D.mro())

結果:

Enter D
Enter B
Enter C
<super: <class 'C'>, <D object>>
Enter A
Leave A
Leave C
Leave B
Leave D
[<class '__main__.D'>, <class '__main__.B'>, <class '__main__.C'>, <class '__main__.A'>, <class 'object'>]