Python面向对象的模式
Python面向对象的模式详细操作教程
面向对象的模式是最常用的模式。这种模式几乎可以在每种编程语言中找到。
如何实现面向对象的模式？
现在让我们看看如何实现面向对象的模式。
# Filename : example.py
# Copyright : 2020 By Lidihuo
# Author by : www.lidihuo.com
# Date : 2020-08-22
class Parrot:
# class attribute
species = "bird"
# instance attribute
def __init__(self, name, age):
self.name = name
self.age = age
# instantiate the Parrot class
blu = Parrot("Blu", 10)
woo = Parrot("Woo", 15)
# access the class attributes
print("Blu is a {}".format(blu.__class__.species))
print("Woo is also a {}".format(woo.__class__.species))
# access the instance attributes
print("{} is {} years old".format( blu.name, blu.age))
print("{} is {} years old".format( woo.name, woo.age))
输出
上面的程序生成以下输出
# Filename : example.py
# Copyright : 2020 By Lidihuo
# Author by : www.lidihuo.com
# Date : 2020-08-22
Blu is a bird
Woo is also a bird
Blu is 10 years old
Woo is 15 years old
说明
该代码包括类属性和实例属性，它们根据输出的要求进行打印。有多种功能构成面向对象模式的一部分。
下面重点介绍使用面向对象的概念及其在Python中的实现的模式。当我们围绕语句块设计程序时，这些语句块围绕函数操作数据，这称为面向过程的程序设计。在面向对象的编程中，有两个主要的实例，分别称为类和对象。
如何实现类和对象变量？
# Filename : example.py
# Copyright : 2020 By Lidihuo
# Author by : www.lidihuo.com
# Date : 2020-08-22
class Robot:
population = 0
def __init__(self, name):
self.name = name
print("(Initializing {})".format(self.name))
Robot.population += 1
def die(self):
print("{} is being destroyed!".format(self.name))
Robot.population -= 1
if Robot.population == 0:
print("{} was the last one.".format(self.name))
else:
print("There are still {:d} robots working.".format(
Robot.population))
def say_hi(self):
print("Greetings, my masters call me {}.".format(self.name))
@classmethod
def how_many(cls):
print("We have {:d} robots.".format(cls.population))
droid1 = Robot("R2-D2")
droid1.say_hi()
Robot.how_many()
droid2 = Robot("C-3PO")
droid2.say_hi()
Robot.how_many()
print("\nRobots can do some work here.\n")
print("Robots have finished their work. So let's destroy them.")
droid1.die()
droid2.die()
Robot.how_many()
运行结果如下：
# Filename : example.py
# Copyright : 2020 By Lidihuo
# Author by : www.lidihuo.com
# Date : 2020-08-22
(Initializing R2-D2)
Greetings, my masters call me R2-D2.
We have 1 robots.
(Initializing C-3PO)
Greetings, my masters call me C-3PO.
We have 2 robots.
Robots can do some work here.
Robots have finished their work. So let's destroy them.
R2-D2 is being destroyed!
There are still 1 robots working.
C-3PO is being destroyed!
C-3PO was the last one.
We have 0 robots.
说明：在这里，我们将总体类变量称为Robot.population，而不是self.population。
