The attributes and properties in a class can be of two types: Class attributes and Instance attributes (Static not supported)
The methods in a class can be of three types: Instance Methods, Class Methods and Static Methods
class Person:
def introduce(self):
print(f"My name is {self.first_name} {self.last_name}")
if __name__ == '__main__':
p1 = Person()
# Create Instance Attributes
p1.first_name = "David"
p1.last_name = "Varghese"
p1.introduce()
print(vars(p1))
# {'first_name': 'David', 'last_name': 'Varghese'} _dict_ Attribute
- Every object in Python has a
__dict__attribute that stores all the writable attributes for that object (For each instance of the object a new one is created) - This special attribute can be accessed using the
vars()method as well (Recommended) - We can add new attributes directly into the class using the this dictionary object
_slots_ Attribute
- If we know in advance all the attributes that are going to be present in our class we can make use of
__slots__attribute to declare them - It is a tuple that holds the all the attributes of the class (It is common across all the instance of the class)
- It provides memory savings over the dictionary object that is created for all the instance of the class (When
__slots__is used__dict__attribute is not created) - Attributes declared using slots also have
__set__and__get__descriptor automatically created - It also provides speed improvement in accessing the instance attributes as the time complexity to access an element in list in worst case O(1) compared to O(n) for dictionary
Understand slots in Python | by Xiaoxu Gao | Towards Data Science