Iterate over object attributes in python [duplicate]

Question

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 

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).

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.

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 

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

Answer 1

Assuming you have a class such as

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

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'] 

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'] 

or if you prefer map/filters.

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

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'] 

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__'])