I want to get the attributes of a class, say:
class MyClass():
a = "12"
b = "34"
def myfunc(self):
return self.a
using MyClass.__dict__
gives me a list of attributes and functions, and even functions like __module__
and __doc__
. While MyClass().__dict__
gives me an empty dict unless I explicitly set an attribute value of that instance.
I just want the attributes, in the example above those would be: a
and b
Method 1: To get the list of all the attributes, methods along with some inherited magic methods of a class, we use a built-in called dir() . Method 2: Another way of finding a list of attributes is by using the module inspect .
Class attributes are the variables defined directly in the class that are shared by all objects of the class. Instance attributes are attributes or properties attached to an instance of a class. Instance attributes are defined in the constructor. Defined directly inside a class.
Python getattr() function. Python getattr() function is used to get the value of an object's attribute and if no attribute of that object is found, default value is returned. Basically, returning the default value is the main reason why you may need to use Python getattr() function.
Use Python's vars() to Print an Object's Attributes The dir() function, as shown above, prints all of the attributes of a Python object.
Try the inspect module. getmembers
and the various tests should be helpful.
EDIT:
For example,
class MyClass(object):
a = '12'
b = '34'
def myfunc(self):
return self.a
>>> import inspect
>>> inspect.getmembers(MyClass, lambda a:not(inspect.isroutine(a)))
[('__class__', type),
('__dict__',
<dictproxy {'__dict__': <attribute '__dict__' of 'MyClass' objects>,
'__doc__': None,
'__module__': '__main__',
'__weakref__': <attribute '__weakref__' of 'MyClass' objects>,
'a': '34',
'b': '12',
'myfunc': <function __main__.myfunc>}>),
('__doc__', None),
('__module__', '__main__'),
('__weakref__', <attribute '__weakref__' of 'MyClass' objects>),
('a', '34'),
('b', '12')]
Now, the special methods and attributes get on my nerves- those can be dealt with in a number of ways, the easiest of which is just to filter based on name.
>>> attributes = inspect.getmembers(MyClass, lambda a:not(inspect.isroutine(a)))
>>> [a for a in attributes if not(a[0].startswith('__') and a[0].endswith('__'))]
[('a', '34'), ('b', '12')]
...and the more complicated of which can include special attribute name checks or even metaclasses ;)
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