python23面向对象

 

1

类中的静态变量，可以被对象和类调用
对于不可变数据类型来说，类变量最好用类名操作
对于可变数据类型来说，对象名的修改是共享的，重新赋值是独立的

'''
创建一个类，每实例化一个对象就计数

'''
class Foo:
    count=0
    def __init__(self):
        Foo.count+=1
f1=Foo()
f2=Foo()
print(f1.count)
print(f2.count)

 

面向对象的三大特性

组合

'''
组合的使用
'''
# 面向对象的三大特性 ： 继承 多态 封装
# 组合
# 人狗大战
class Dog:
    def __init__(self,name,aggr,hp,kind):
        self.name = name
        self.aggr = aggr
        self.hp = hp
        self.kind = kind

    def bite(self,person):
        person.hp -= self.aggr

class Person:
    def __init__(self,name,aggr,hp,sex):
        self.name = name
        self.aggr = aggr
        self.hp = hp
        self.sex = sex
        self.money = 0

    def attack(self,dog):
        dog.hp -= self.aggr

    def get_weapon(self,weapon):
        if self.money >= weapon.price:
            self.money -= weapon.price
            self.weapon = weapon
            self.aggr += weapon.aggr
        else:
            print("余额不足，请先充值")

class Weapon:
    def __init__(self,name,aggr,njd,price):
        self.name = name
        self.aggr = aggr
        self.njd = njd
        self.price = price

    def hand18(self,person):
        if self.njd > 0:
            person.hp -= self.aggr * 2
            self.njd -= 1

alex = Person('alex',0.5,100,'不详')
jin = Dog('金老板',100,500,'teddy')
w = Weapon('打狗棒',100,3,998)
# alex装备打狗棒
alex.money += 1000
alex.get_weapon(w)
print(alex.weapon)
print(alex.aggr)
alex.attack(jin)
print(jin.hp)
alex.weapon.hand18(jin)
print(jin.hp)

# 组合 ：一个对象的属性值是另外一个类的对象
#        alex.weapon 是 Weapon类的对象

 

 

'''
求圆环的面积
# 圆形类
# 圆环类
'''

from math import pi
class Circle:
    def __init__(self,r):
        self.r = r
    def area(self):
        return self.r**2 * pi
    def perimeter(self):
        return 2*pi*self.r

class Ring:
    def __init__(self,outside_r,inside_r):
        self.outside_c = Circle(outside_r)
        self.inside_c = Circle(inside_r)
    def area(self):
        return self.outside_c.area() - self.inside_c.area()
    def perimeter(self):
        return self.outside_c.perimeter()+self.inside_c.perimeter()

# ring = Ring(20,10)
# print(ring.area())
# print(ring.perimeter())

# 创建一个老师类
# 老师有生日
# 生日也可以是一个类
# 组合
class Birthday:
    def __init__(self,year,month,day):
        self.year = year
        self.month = month
        self.day = day

class Course:
    def __init__(self,course_name,period,price):
        self.name = course_name
        self.period = period
        self.price = price

class Teacher:
    def __init__(self,name,age,sex,birthday):
        self.name = name
        self.age = age
        self.sex = sex
        self.birthday =birthday
        self.course = Course('python','6 month',2000)

b = Birthday(2018,1,16)
egg = Teacher('egon',0,'女',b)
print(egg.name)
print(egg.birthday.year)
print(egg.birthday.month)
print(egg.course.price)