Objects are mutable
Related code
class Dog:
"""Represents a dog."""
dog = Dog()
dog.name = "Murki"
dog.age = 2
You can change the state of an object by making an assignment to one of its attributes. For example, to change the name and age of a dog, you can modify the values of name and age:
...
>>> dog.name
Murki
>>> dog.age
2
>>> dog.name = "Rreshki"
>>> dog.age = 3
>>> dog.name, dog.age
('Rreshki', 3)
You can also update the value of the attribute based on its current value:
... >>> dog.age 3 >>> dog.age = dog.age + 2 >>> dog.age 5
pass
A class definition with no statement in its body gives error:
class Dog:
IndentationError('expected an indented block after class definition on line 1', ('<string>', 1, 11, 'class Dog:\n', 1, -1))
>>>
We can write a docstring, or we can use pass keyword,
which is used as a placeholder for the code to come. In our case we can use it to avoid error:
class Dog:
pass
Exercises
class Room:
pass
r = Room()
r.name = "Living Room"
r.lights_on = False
r.lights_on = True
What is the value of the following expressions at the end of execution of the above script?
| r.name: | |
| r.lights_on: |
Exercises
Create a class, Car
Create a dog, my_car, with two attributes, brand and year.
Change my_car's brand
Add one year to my_car
Create a class, Cup
Create a cup, c, with two attributes, color and volume.
Change c's color
Add 50 to c's volume
Create a class, Fruit
Create a fruit, f, with one attribute, type.
Change f's type
Create a class, Shoe
Create a shoe, s, with one attribute, size.
Add 1 to s's size
class Horse:
pass
h = Horse()
h.name = "Storm"
h.age = 5
h.color = "Brown"
h.color = "Black"
h.age += 2
What is the value of the following expressions at the end of execution of the above script?
| h.color: | |
| h.age: |