遍历python中的对象属性

Iterate over object attributes in python(遍历python中的对象属性)

问题描述

我有一个带有多个属性和方法的 python 对象.我想迭代对象属性.

I have a python object with several attributes and methods. I want to iterate over object attributes.

class my_python_obj(object):
    attr1='a'
    attr2='b'
    attr3='c'

    def method1(self, etc, etc):
        #Statements

我想生成一个包含所有对象属性及其当前值的字典，但我想以动态方式进行(所以如果以后我添加另一个属性，我不必记得将我的函数更新为好).

I want to generate a dictionary containing all of the objects attributes and their current values, but I want to do it in a dynamic way (so if later I add another attribute I don't have to remember to update my function as well).

在 php 中的变量可以用作键，但在 python 中的对象是不可接受的，如果我为此使用点表示法，它会创建一个带有我的 var 名称的新属性，这不是我的意图.

In php variables can be used as keys, but objects in python are unsuscriptable and if I use the dot notation for this it creates a new attribute with the name of my var, which is not my intent.

只是为了让事情更清楚:

Just to make things clearer:

def to_dict(self):
    '''this is what I already have'''
    d={}
    d["attr1"]= self.attr1
    d["attr2"]= self.attr2
    d["attr3"]= self.attr3
    return d

·

def to_dict(self):
    '''this is what I want to do'''
    d={}
    for v in my_python_obj.attributes:
        d[v] = self.v
    return d

更新:属性是指这个对象的变量，而不是方法.

Update: With attributes I mean only the variables of this object, not the methods.

推荐答案

假设你有一个类如

>>> class Cls(object):
...     foo = 1
...     bar = 'hello'
...     def func(self):
...         return 'call me'
...
>>> obj = Cls()

在对象上调用 dir 会返回该对象的所有属性，包括 python 特殊属性.虽然有些对象属性是可调用的，比如方法.

calling dir on the object gives you back all the attributes of that object, including python special attributes. Although some object attributes are callable, such as methods.

>>> dir(obj)
['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'bar', 'foo', 'func']

您始终可以使用列表推导过滤掉特殊方法.

You can always filter out the special methods by using a list comprehension.

>>> [a for a in dir(obj) if not a.startswith('__')]
['bar', 'foo', 'func']

或者如果您更喜欢地图/过滤器.

or if you prefer map/filters.

>>> filter(lambda a: not a.startswith('__'), dir(obj))
['bar', 'foo', 'func']

如果要过滤掉方法，可以使用内置的callable作为检查.

If you want to filter out the methods, you can use the builtin callable as a check.

>>> [a for a in dir(obj) if not a.startswith('__') and not callable(getattr(obj, a))]
['bar', 'foo']

您还可以使用检查您的类与其实例对象之间的差异.

You could also inspect the difference between your class and its instance object using.

>>> set(dir(Cls)) - set(dir(object))
set(['__module__', 'bar', 'func', '__dict__', 'foo', '__weakref__'])

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