Python基础学习（八）-----面向对象编程

一. 面向对象

1. 特征

1. 封装
2. 继承
3. 多态
   (1) 属于同一类型的不同事例

class Book:
    count = 0

    #初始化执行
    def __init__(self,title,price=0.0,author=None):  #self自身的东西等于传过来的东西
        self.title = title
        self.price = price
        self.author = author
        Book.count +=1

    #删除对象执行
    def __del__(self):
        Book.count -= 1

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

    def __repr__(self):  # 定义对象在交互式提示符下显示方式
        return '<book {} at {}>'.format(self.title, id(self))

    def __str__(self):  # 打印时执行
        return '<book {} at {}>'.format(self.title, id(self))

    def cls_method(cls):
        print('类函数，与实例无关')
    
    #@staticmethod  #加上可以通过实例调用 
    def ststic_method():
        print('静态函数，逻辑上与实例无关')

if __name__ =='__main__':
    book = Book('Python classical',price=29.0,author='Tom')
    book2 = Book('Flask')
    book3 = Book('ASP.net')

    del(book3)

    print('number of book:{}'.format(Book.count))
    Book.cls_method(book)
    Book.ststic_method()

过滤值

import datetime
class Student:

    def __init__(self,name,gender,birthdate):
        self.name = name
        self.gender = gender
        self.birthdate = birthdate

    @property #表明属性,可以进一步过滤
    def age(self):
        return datetime.date.today().year - self.birthdate.year
    
    @age.setter #设置器
    def age(self,value):
        raise AttributeError('禁止赋值年龄！')
    
    @age.deleter #删除器
    def age(self):
        raise AttributeError('年龄不能删除')

    def get_age(self): #过滤，不可以进一步过滤
        return datetime.date.today().year - self.birthdate.year

if __name__ == '__main__':
   s = Student('Tom',20,datetime.date(1992,3,1))
   print(s.birthdate)
   print(s.get_age())
   print(s.age)

继承

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'<employee:{}>'.format(self.name)

    def working(self):
        print('enployee:{} is working',format(self.name))

#继承
class Programmer(Employee):
    def __init__(self,department,name,birthdate,salary,speciality,project):
        super().__init__(department,name,birthdate,salary)
        self.speciality = speciality
        self.project = project

    def working(self): #多态
        print('Programmer: {} is developing program{}'.format(self.name,self.project))

class HR(Employee):
    def __init__(self,department,name,birthdate,salary,qualification_level=1):
        Employee.__init__(self,department,name,birthdate,salary)
        self.qualifaction_level = qualification_level

    def working(self):
        print('HR:{} is interviewing '.format(self.name))

if __name__ == '__main__':
    p = Programmer('Technology', '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.age)

    hr = HR('HR','Marry',datetime.date(1992,4,4),6000,qualification_level=3)
    hr.give_raise(.1)
    print(hr.salary)
    hr.working()

类和类的关联

import datetime

class Department:
    def __init__(self,department,phone,manager):
        self.department = department
        self.phone = phone
        self.manager = manager

    def __repr__(self):
        return'<department:{}>'.format(self.department)

class Employee:
    def __init__(self,department: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'<employee:{}>'.format(self.name)

    def working(self):
        print('enployee:{} is working',format(self.name))

#继承
class Programmer(Employee):
    def __init__(self,department,name,birthdate,salary,speciality,project):
        super().__init__(department,name,birthdate,salary)
        self.speciality = speciality
        self.project = project

    def working(self): #多态
        print('Programmer: {} is developing program{}'.format(self.name,self.project))

class HR(Employee):
    def __init__(self,department,name,birthdate,salary,qualification_level=1):
        Employee.__init__(self,department,name,birthdate,salary)
        self.qualifaction_level = qualification_level

    def working(self):
        print('HR:{} is interviewing '.format(self.name))

if __name__ == '__main__':
    dep = Department('Techonology','010-8771652','Dasan')
    p = Programmer(dep,'Peter',datetime.date(1990,3,1),8000,'Flask','XMall')
    p.give_raise(.2,.1)
    print(p.salary)
    print(p.department.phone)
    print(p.department.manager)