CODEWITHSUNDEEP
pythonpython-3.x
Djangonow
Djangonow

Reputation: 433

How to know attributes vs methods in Python object?

How do you know attributes vs methods in Python object? When using the dir method it only list everything for example dir('string').

Upvotes: 3

Views: 487

Answers (1)

GPhilo
GPhilo

Reputation: 19123

You can test the attributes's type:

from types import MethodType
from pprint import pprint

class A(object):
  def __init__(self) -> None:
    self._field = 3
    self._callable_field = lambda x: x
  
  def my_method(self):
    pass

  @classmethod
  def my_static_method(cls):
    pass

  def __str__(self) -> str:
    return repr(self)

A.another_method = lambda self: None

a = A()
pprint([(d, type(getattr(a,d)) is MethodType) for d in dir(a)])

prints

[('__class__', False),
 ('__delattr__', False),
 ('__dict__', False),
 ('__dir__', False),
 ('__doc__', False),
 ('__eq__', False),
 ('__format__', False),
 ('__ge__', False),
 ('__getattribute__', False),
 ('__gt__', False),
 ('__hash__', False),
 ('__init__', True),
 ('__init_subclass__', False),
 ('__le__', False),
 ('__lt__', False),
 ('__module__', False),
 ('__ne__', False),
 ('__new__', False),
 ('__reduce__', False),
 ('__reduce_ex__', False),
 ('__repr__', False),
 ('__setattr__', False),
 ('__sizeof__', False),
 ('__str__', True),              # <<<<<<<<<<
 ('__subclasshook__', False),
 ('__weakref__', False),
 ('_callable_field', False),     # <<<<<<<<<<
 ('_field', False),              # <<<<<<<<<<
 ('another_method', True),       # <<<<<<<<<<
 ('my_method', True),            # <<<<<<<<<<
 ('my_static_method', True)]     # <<<<<<<<<<

Note that this won't print True for builtin methods that are not explicitly defined in the class definition (or attached later, see __str__ and another_method above). Note, also, that unlike testing for callable, this actually catches the distinction between methods and callable attributes.

Upvotes: 5

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