Why do custom classes and built-in classes in Python have different ways of adding attributes?

Asked Dec 11 '19 at 06:06

Active Jul 13 '20 at 05:40

Viewed 45 times

class A():
    def __init__(self):
        self.a = 1
        self.b = 2

a = A()
a.zzz = 2

b = int()
b.zzz = 2

Traceback (most recent call last):
  File "/home/user/test.py", line 10, in <module>
    b.zzz = 2
AttributeError: 'int' object has no attribute 'zzz'

I don't understand the difference between the class I defined and the int class, why can a custom class add a new attribute, and the original int cannot.

edited Jul 13 '20 at 05:40

asked Dec 11 '19 at 06:06

sim

2

Does this answer your question? [Can I add custom methods/attributes to built-in Python types?](https://stackoverflow.com/questions/4698493/can-i-add-custom-methods-attributes-to-built-in-python-types) – Kent Shikama Dec 11 '19 at 06:12
1

It is only possible if the object implements __dict__() method. You can check it by using dir() method. – Tamoor Salah-U-Din Dec 11 '19 at 06:23
@TamoorSalah-U-Din `__dict__` is not a method, it's an attribute. – bruno desthuilliers Dec 11 '19 at 08:12

Why do custom classes and built-in classes in Python have different ways of adding attributes?

0 Answers0