如何获取属于Python 3中特定类的所有属性（继承的属性除外）的值

Question

How (in Python 3) to get values of all properties that belong to specific class. I need ONLY those values (properties) that defined in specific class without inherited ones.

Here is some example:

class A(object):
    def __init__(self, color):
        self._color = color

    @property
    def color(self):
        return self._color

class B(A):
    def __init__(self, color, height, width):
        super().__init__(color)
        self._height = height
        self._width = width

    @property
    def height(self):
        return self._height

    @property
    def width(self):
        return self._width

and here is a code for fetching all values (including inherited):

b_inst = B('red', 10, 20)
val = [{p: b_inst.__getattribute__(p)} for p in dir(B)
       if isinstance(getattr(B, p), property)]

print(val)

>> [{'color': 'red'}, {'height': 10}, {'width': 20}]

Now, I just want to retrieve values of properties defined ONLY in class B , ie height and width .

Answer 1

Note that in Python "property" has a very specific meaning (the builtin property type). If you're only concerned about this then you just have to lookup your child class's __dict__ :

val = [p.__get__(c) for k, p in type(c).__dict__.items() if isinstance(p, property)]

If you want something that works on any arbitrary attribute then what you ask for is just not possible, since Python objects (with a few exceptions) are dict-based (vs struct-based like in C++ or Java) and dynamic (any piece of code can add / remove arbitrary attributes on a per-instance basis) so there's no fix schema nor class-level definition of what attributes a given object may or not possess.

Answer 2

If property == to attribute , from the doc :

Attribute assignments and deletions update the instance's dictionary, never a class's dictionary.

So even you do self._color = color on a base class, you are assigning that attribute/property to the instance of the B class.

So, at least that you save info tied to the attribute/property for consult latter, I don't think that given how Python works, you will be able to determine to what class the method in which a property was assigned belong to , that is how your question means in Python.

I hope that this helps you to clarify the OOP model of Python.

If you are referring to Python's properties , then the @bruno answer is perfect. I will still leave this answer here because is kind of related to your topic and could be useful for readers.