如何在Python中使用方法重载？ [英] How do I use method overloading in Python?

问题描述

我尝试在Python中实现方法重载：

I am trying to implement method overloading in Python:

class A:
    def stackoverflow(self):    
        print 'first method'
    def stackoverflow(self, i):
        print 'second method', i

ob=A()
ob.stackoverflow(2)

但输出为第二种方法2 ;类似地：

class A:
    def stackoverflow(self):    
        print 'first method'
    def stackoverflow(self, i):
        print 'second method', i

ob=A()
ob.stackoverflow()

提供

Traceback (most recent call last):
  File "my.py", line 9, in <module>
    ob.stackoverflow()
TypeError: stackoverflow() takes exactly 2 arguments (1 given)

如何使这项工作？

推荐答案

em>覆盖。在Python中，你在一个函数中做这些：

It's method overloading not method overriding. And in Python, you do it all in one function:

class A:

    def stackoverflow(self, i='some_default_value'):    
        print 'only method'

ob=A()
ob.stackoverflow(2)
ob.stackoverflow()

您不能在Python中使用两个相同名称的方法， to。

You can't have two methods with the same name in Python -- and you don't need to.

请参阅默认参数值部分。请参见最少惊讶

See the Default Argument Values section of the Python tutorial. See "Least Astonishment" in Python: The Mutable Default Argument for a common mistake to avoid.

编辑：请参阅 PEP 443 了解有关Python 3.4中新的单一分派通用函数的信息。

Edit: See PEP 443 for information about the new single dispatch generic functions in Python 3.4.

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