Python字典从对象的字段 [英] Python dictionary from an object's fields

问题描述

您是否知道是否有内置函数从任意对象构建字典？我想做这样的事情：

 >>> Foo类：
 ... bar ='hello'
 ... baz ='world'
 ... 
>>> f = Foo（）
>>>道具（f）
 {'bar'：'hello'，'baz'：'world'} 
  

注意：不应包含方法。

解决方案

请注意，当前版本的Python的最佳做法是使用新风格类，即

  class Foo（object）：
 ... 
  

此外，对象和类之间有区别。要从任意的对象构建字典，使用 __ dict __ 就足够了。通常，您将在类级别声明您的方法，并在实例级别声明您的属性，因此 __ dict __ 应该是正常的。例如：

 >>> A类（对象）：
 ... def __init __（self）：
 ... self.b = 1 
 ... self.c = 2 
 ... def do_nothing（self）：
 ... pass 
 ... 
>>> a = A（）
>>>> a .__ dict__ 
 {'c'：2，'b'：1} 
  

，取决于你想做什么，可能会很好的继承从dict。然后，你的类已经是一个字典，如果你想要你可以覆盖getattr和/或setattr来调用和设置dict。例如：

  class Foo（dict）：
 def __init __（self）：
 pass 
 def __getattr __（self，attr）：
 return self [attr] 
 
＃etc ... 
  

Do you know if there is a built-in function to build a dictionary from an arbitrary object? I'd like to do something like this:

>>> class Foo:
...     bar = 'hello'
...     baz = 'world'
...
>>> f = Foo()
>>> props(f)
{ 'bar' : 'hello', 'baz' : 'world' }

NOTE: It should not include methods. Only fields.

解决方案

Note that best practice in current versions of Python is to use new-style classes, i.e.

class Foo(object):
...

Also, there's a difference between an 'object' and a 'class'. To build a dictionary from an arbitrary object, it's sufficient to use __dict__. Usually, you'll declare your methods at class level and your attributes at instance level, so __dict__ should be fine. For example:

>>> class A(object):
...   def __init__(self):
...     self.b = 1
...     self.c = 2
...   def do_nothing(self):
...     pass
...
>>> a = A()
>>> a.__dict__
{'c': 2, 'b': 1}

Alternatively, depending on what you want to do, it might be nice to inherit from dict. Then your class is already a dictionary, and if you want you can override getattr and/or setattr to call through and set the dict. For example:

 class Foo(dict):
     def __init__(self):
         pass
     def __getattr__(self, attr):
         return self[attr]

     # etc...

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