python属性装饰器 [英] python property decorator

问题描述

可能重复：

我对以下代码中看到的装饰器 @property 有疑问。有人会足够仁慈地完全解释为什么有人会使用 @property 装饰器吗？我知道 @property 等效于 isActive = property（isActive），但是method属性实际上对它的参数做了什么？如果我要从 InputCell 类调用 isActive 方法，实际上会发生什么？

I have a question about the decorator @property that I've seen in the following code. Could someone be kind enough to completely explain why someone would use the @property decorator? I know @property is equivalent to isActive = property(isActive) but what does the method property actually do to it's parameter? If I were to call the isActive method from the InputCell class what would actually happen? Thanks in advance.

class InputCell(object):
    def __init__(self, ix, iy, inputData):
        self.ix = ix
        self.iy = iy
        self.InputData = inputData

    @property
    def isActive(self):
        return self.InputData[self.ix][self.iy]

推荐答案

这只是语法糖。

一种有用的方法是，如果您想更改以前是的内容一个简单的变量，用于使用其他代码实际计算或验证的内容。如果将其设置为属性，则可以在不破坏任何现有代码的情况下执行此操作。另一种方法是用于对象属性的缓存，延迟初始化等。

One way this can be useful is if you want to change something that previously was a simple variable to something that's actually computed or validated with other code. If you make it a property, you can do this without breaking any existing code. Another way is for caching, lazy initialization, etc., of object attributes.

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