本文介绍了属性 getter/setter 在 Python 2 中不起作用的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我对 python 中的属性有点困惑.考虑以下代码

I'm a bit confused about properties in python. Consider the following code

class A:
    @property
    def N(self):
        print("A getter")
        return self._N
    @N.setter
    def N(self,v):
        print("A setter")
        self._N = v

    def __init__(self):
        self._N = 1

class B:
    @property
    def N(self):
        print("B getter")
        return self.a.N
    @N.setter
    def N(self,v):
        print("B setter")
        self.a.N = v

    def __init__(self):
        self.a = A()

if __name__ == '__main__':
    b=B()
    b.N = 2
    print(b.N, b.a.N)
    b.N = 3
    print(b.N, b.a.N)

B 应该类似于 A 的包装器.它使用 getter 和 setter 将 A 的属性映射到自身上(当然也可以通过继承来实现).问题是,它在 python2.6 中根本不能按预期工作,而在 python3 中:

B should be something like a wrapper for A. It uses getters and setters to map A's properties on itself (of course one could also do it via inheritance).The problem is, that it simply doesn't work as expected in python2.6 while it does in python3:

> python2 test.py
A getter
(2, 1)
A getter
(3, 1)

> python3 test.py
B setter
A setter
B getter
A getter
A getter
2 2
B setter
A setter
B getter
A getter
A getter
3 3

是我做错了什么还是问题出在哪里?

Am I doing anything wrong or where exactly is the problem?

推荐答案

A 和 B 必须是 Python 2.x 中的新式类.

A and B must be new-style classes in Python 2.x.

property([fget[, fset[, fdel[, doc]]]])

返回新式类(派生自object).

所以如果你从 object

class A(object):
   ...

class B(object):
    ...

您的代码将按预期工作.

Your code will work as expected.

这篇关于属性 getter/setter 在 Python 2 中不起作用的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

07-23 07:51
查看更多