[X-Village] Lesson04-Inheritance¶
by 介誠
Review¶
- Define a class
In [19]:
class Car():
def __init__(self):
self.wheels_number = 4
def forward(self):
print("Ba! Ba! Ba! I'm CAR!")
def turn_right(self): pass
def turn_left(self): pass
- Creates a new instance of the class
In [20]:
give_me_a_car = Car()
- Call
forward()method
In [21]:
give_me_a_car.forward()
Ba! Ba! Ba! I'm CAR!
Intro¶
Inheritance (繼承): creating a new class from an existing class but with some additions or changes
No Inheritance¶
In [1]:
class Car():
def __init__(self): pass
def forward(self): pass
def turn_right(self): pass
def turn_left(self): pass
class Bus():
def __init__(self): pass # the same as Car()
def forward(self): pass # the same as Car()
def turn_right(self): pass # the same as Car()
def turn_left(self): pass # the same as Car()
def open_door(self): pass # add the method
class Truck():
def __init__(self): pass # the same as Car()
def forward(self): pass # the same as Car()
def turn_right(self): pass # the same as Car()
def turn_left(self): pass # the same as Car()
def open_trunck(self): pass # add the method
With Inheritance (不要重造輪子)¶
In [2]:
class Car():
def __init__(self): pass
def forward(self): pass
def turn_right(self): pass
def turn_left(self): pass
# 繼承了 Car 的屬性和方法
class Bus(Car):
def open_door(self): pass # add the method
# 繼承了 Car 的屬性和方法
class Truck(Car):
def open_trunck(self): pass # add the method
Basic¶
- parent, superclass, or base class
In [1]:
class Car():
pass
- child, subclass, or derived class
In [2]:
class Bus(Car):
pass
- create an object from each class
In [3]:
give_me_a_car = Car()
give_me_a_bus = Bus()
In [5]:
print(type(give_me_a_car))
<class '__main__.Car'>
In [6]:
print(type(give_me_a_bus))
<class '__main__.Bus'>
Example¶
In [10]:
class Car():
def __init__(self):
self.wheels_number = 4
def shout(self):
print("I'm a Car!")
class Bus(Car):
pass
In [11]:
give_me_a_car = Car()
give_me_a_bus = Bus()
In [12]:
class Car():
def __init__(self):
self.wheels_number = 4
def shout(self):
print("I'm a Car!")
class Bus(Car):
pass
In [15]:
# parent
give_me_a_car.shout()
print(give_me_a_car.wheels_number)
I'm a Car! 4
In [14]:
# child
give_me_a_bus.shout()
print(give_me_a_bus.wheels_number)
I'm a Car! 4
Exercise1 - 列入計分¶
- 這世界充滿著許多動物，幾乎所有的動物都會「叫」、「吃飯」、「睡覺」...
- 請你定義一個 class
Animal- 設定它是四隻腳,
feet_number = 4 - 設定它會說話, 說
"Hello! I'm an animal."
- 設定它是四隻腳,
- 在定義一個 child class
Dog，繼承自 parent classAnimal
- 驗證是否正確：
dog = Dog()
print(dog.feet_number) # 要印出 4
dog.shout() # 要印出 "Hello! I'm an animal."
[X-Village] Lesson04-Inheritance by 介誠