Python概述（8）

面向对象

特征

封装
继承
多态

# 默认值参数放在命名参数后面
def _init_(self,title,price=0.0,author=None):
    self.title = title
    self.price = price
    self.author = author

def _repr_(self):
    # 0x表示16进制，id(self)表示全局变量
    return '<图书:{} at 0x{}>'.format(self.title,id(self))

def _str_(self):
    return '<图书:{},定价:{}>'.format(self.title,self.price)

def print_info(self):
    print(self.title,self.price,self.author)

# if _name_ == '_main_':
#   book = Book('Python经典',price=29.9,author='Tom')
#   book.print_info()     

b = main.Book('C#')
print(b)

Output: <图书:C# at 0x51767664>

Class Book:
    count = 0
    def _init_(self,title,price=0.0,author=None):
        self.title = title
        self.price = price
        self.author = author
        Book.count += 1

    def _repr_(self):
        return '<图书:{} at 0x{}>'.format(self.title,id(self))

    def _str_(self):
        return '<图书:{},定价:{}>'.format(self.title,self.price)

    def print_info(self):
        print(self.title,self.price,self.author)

    if _name_ == '_main_':
       book1 = Book('Python')
       book2 = Book('C#')
       book3 = Book('Java')
       
       del(book3)

print('图书数量:{}'.format(Book.count))

Output: 图书数量:3

import datetime

class Student:
    def _init_(self,name,birthdate):
        self.name = name
        self.birthdate = birthdate
    
    @property
    def age(self):
         return datetime.date.today().year - self.birthdate.year    
    
    @age.setter
    def age(self,value):
        raise AttributeError('禁止赋值年龄！')
    
    @age.deleter
    def age(self):
        raise AttributeError('年龄不能删除')

if _name_ == '_main_':
    s = Student('Tom',datetime.date(1992,3,1))
    print(s.birthdate)
    print(s.age)
    s.birthdate = datetime.date(1992,8,2)
## name可以删除，但是age不可以
#   del(s.name)
#   print(s.name)
# Output: AttributeError: 'Student' object has no attribute 'name'
    del(s.age)
    print(s.age)

Output: AttributeError: 年龄不能删除

import math

class Circle:
    def _init_(self,radius):
        self.radius = radius
    
    @property
    def area(self):
        return math.pi * self.radius ** 2
    
    # def get_area(self):
    #    return math.pi * self.radius ** 2

c = Circle(4.0)
print("圆的面积是:{}".format(c.area))

Example:

import datetime

class Employee:
    def _init_(self,department,name,birthdate,salary):
        self.department = department
        self.name = name
        self.birthdate = birthdate
        self.salary = salary
   
   @property
   def age(self):
       return datetime.date.today().year - self.birthdate.year
    
    def give_raise(self,percent,bonus=.0):
        self.salary = self.salary * (1 + percent + bonus)
         
    def _repr_(self):
        return '<员工:{}>'.format(self.name)
    
    def working(self):
        print('员工:{},在工作...'.format(self.name))

# 继承
class Programer(Employee):
    def _init_(self,department,name,birthdate,salary,specialty,project):
        super()._init_(department,name,birthdate,salary)
        self.salary = specialty
        self.project = project
    
    def working(self):
        print('程序员:{}在开发项目:{}...'.format(self.name,self.project))

class HR(Employee):
    def _init_(self,department,name,birthdate,salary,specialty,qualification_level = 1):
        Employee._init_(self,department,name,birthdate,salary)
        self.qualification_level = qualification_level
    
    def working(self):
        print('人事:{}正在面试新员工...'.format(self.name))
    
       
if _name_ == '_main_':
    p = Programer('技术部'，‘Peter’,datetime.date(1990,3,3),8000,'Flask','CRM')
    print(p.department)
    print(p.salary)
    p.give_raise(.2,.1)
    print(p.salary)
    p.working()
    print(p.page)

    hr = HR('人事部','Marry',datetime.date(1992,4,4),6000,qualification_level=1)
    hr.give_raise()
    print(hr.salary)
    hr.working()

Output:
<员工：Peter>
技术部
8000
10400.0
程序员：Peter在开发项目: CRM…
26
6600.000000000001
人事: Marry正在面试新员工…

来源：CSDN

作者：晨曦skyyyy

链接：https://blog.csdn.net/mingxisky/article/details/103483342

标签

python继承

return

python