OOP总结

what's OOPClasses in pythonPython Objects(instances)How to define a class in PythonInstance AttributesInstance Methods调整属性 Python Object Inheritance

参考：https://realpython.com/python3-object-oriented-programming/#what-is-object-oriented-programming-oop

what’s OOP

Definition: is a programming paradigm which provides a means of structuring programs so that properties and behaviors are bundled into individual objects.类似于一个人有名字、年龄、地址等属性

Classes in python

Definition: classes are used to create user-defined data structures that contain arbitrary information about something.

Python Objects(instances)

实例

How to define a class in Python

Instance Attributes

self是用来记录每一个类的实例 class Dog: # Class Attribute species = 'mammal' # Initializer / Instance Attributes def __init__(self, name, age): self.name = name self.age = age

作业：Using the same Dog class, instantiate three new dogs, each with a different age. Then write a function called, get_biggest_number(), that takes any number of ages (*args) and returns the oldest one. Then output the age of the oldest dog like so: The oldest dog is 7 years old.

class Dog: # Class Attribute species = 'mammal' # Initializer / Instance Attributes def __init__(self, name, age): self.name = name self.age = age # Instantiate the Dog object jake = Dog("Jake", 7) doug = Dog("Doug", 4) william = Dog("William", 5) # Determine the oldest dog def get_biggest_number(*args): return max(args)

Instance Methods

用来获取实例内容 class Dog: # Class Attribute species = 'mammal' # Initializer / Instance Attributes def __init__(self, name, age): self.name = name self.age = age # instance method def description(self): return "{} is {} years old".format(self.name, self.age) # instance method def speak(self, sound): return "{} says {}".format(self.name, sound) # Instantiate the Dog object mikey = Dog("Mikey", 6) # call our instance methods print(mikey.description()) print(mikey.speak("Gruff Gruff"))

调整属性

>>> class Email: ... def __init__(self): ... self.is_sent = False ... def send_email(self): ... self.is_sent = True ... >>> my_email = Email() >>> my_email.is_sent False >>> my_email.send_email() >>> my_email.is_sent True

Python Object Inheritance

# Parent class class Dog: # Class attribute species = 'mammal' # Initializer / Instance attributes def __init__(self, name, age): self.name = name self.age = age # instance method def description(self): return "{} is {} years old".format(self.name, self.age) # instance method def speak(self, sound): return "{} says {}".format(self.name, sound) # Child class (inherits from Dog class) class RussellTerrier(Dog): def run(self, speed): return "{} runs {}".format(self.name, speed) # Child class (inherits from Dog class) class Bulldog(Dog): # 继承 def run(self, speed): return "{} runs {}".format(self.name, speed) # Child classes inherit attributes and # behaviors from the parent class jim = Bulldog("Jim", 12) print(jim.description()) # Child classes have specific attributes # and behaviors as well print(jim.run("slowly"))