python - 继承和基类方法调用python

Question

我希望基类中的方法调用同一个类中的另一个方法，而不是继承类中的覆盖方法。我想打印出下面的代码

B 类:6

A 类:9

这可以做到吗？

---

# Base class definition
class ClassA(object):
    def __init__(self):
        print("Initializing A")

    # hoping that this function is called by this class's printFnX
    def fnX(self, x):
        return x**2

    def printFnX(self, x):
        print("ClassA:",self.fnX(x))

# Inherits from ClassA above
class ClassB(ClassA):
    def __init__(self):
        print("initizlizing B")

    def fnX(self, x):
        return 2*x

    def printFnX(self, x):
        print("ClassB:", self.fnX(x))
        ClassA.printFnX(self,x)

bx = ClassB()
bx.printFnX(3)

Answer 1

恭喜，您已经发现了 Python 双下划线名称重整的激励用例:-)

有关详细信息和已解决的示例，请参阅:http://docs.python.org/tutorial/classes.html#private-variables在 http://docs.python.org/reference/expressions.html#atom-identifiers .

以下是如何在您的示例中使用它:

# Base class definition
class ClassA(object):
    def __init__(self):
        print("Initializing A")

    # hoping that this function is called by this class's printFnX
    def fnX(self, x):
        return x**2
    __fnX = fnX

    def printFnX(self, x):
        print("ClassA:",self.__fnX(x))

# Inherits from ClassA above
class ClassB(ClassA):
    def __init__(self):
        print("initizlizing B")

    def fnX(self, x):
        return 2*x

    def printFnX(self, x):
        print("ClassB:", self.fnX(x))
        ClassA.printFnX(self,x)

bx = ClassB()
bx.printFnX(3)

用例被描述为实现 Open-Closed Principle 的一种方式在“子类化的艺术”中找到 http://www.youtube.com/watch?v=yrboy25WKGo&noredirect=1 .