你如何编程设置在Python属性？ [英] How do you programmatically set an attribute in Python?

问题描述

假设我有一个Python对象 X 和一个字符串取值，我怎么设置属性取值在 X ？所以：

 ＆GT;＆GT;＆GT; X = SomeObject（）
＆GT;＆GT;＆GT; ATTR ='myAttr
＆GT;＆GT;＆GT; ＃魔高一尺这​​里
＆GT;＆GT;＆GT; x.myAttr
'魔法'
 

有什么魔力？这样做的目的，顺便说一句，缓存调用 X .__ GETATTR __（）。

解决方案

  SETATTR（X，ATTR，魔力）
 

有关它的帮助：

 ＆GT;＆GT;＆GT;帮助（SETATTR）
帮助的模块__builtin__内置函数SETATTR：SETATTR（...）
    SETATTR（对象名称，值）    设置对象上的指定属性; SETATTR（X，'Y'，v）为相当于
    ``xy格式的= V'。
 

编辑：但是，您应注意（在评论中指出），你不能这样对待对象的纯粹的实例。但它可能是你有对象的简单子类，它会正常工作。我强烈敦促O.P.永远不会使对象的实例这样的。

Suppose I have a python object x and a string s, how do I set the attribute s on x? So:

>>> x = SomeObject()
>>> attr = 'myAttr'
>>> # magic goes here
>>> x.myAttr
'magic'

What's the magic? The goal of this, incidentally, is to cache calls to x.__getattr__().

解决方案

setattr(x, attr, 'magic')

For help on it:

>>> help(setattr)
Help on built-in function setattr in module __builtin__:

setattr(...)
    setattr(object, name, value)

    Set a named attribute on an object; setattr(x, 'y', v) is equivalent to
    ``x.y = v''.

Edit: However, you should note (as pointed out in comment) that you can't do that to a "pure" instance of object. But it is likely you have a simple subclass of object where it will work fine. I would strongly urge the O.P. to never make instances of object like that.

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