45----类的组合

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组合

• 一个类和另一个类组合在一起
• 指的是在一个类中，用另一个类的对象作为该类的属性
• 是一种包括的关系

作用

• 减少重复代码

class  People:
    def __init__(self ,name ,age ,sex ,year ,mon ,day):
        self.name = name
        self.age = age
        self.sex = sex
        self.birth = Date(year ,mon ,day)
    def talk(self):
        print("talking")

class Dog:
    def __init__(self, name, year, mon, day):
        self.name = name
        self.birth = Date(year, mon, day)
    def talk(self):
        print("旺旺")

class Date:
    def __init__(self ,year ,mon ,day):
        self.year = year
        self.mon = mon
        self.day = day
    def get_birth(self):
        print("生日：%s年-%s月-%s日" %(self.year, self.mon, self.day))


r = People("bone", 26, "男", 1990, 12, 30)
print(r.name, r.age)  # bone26
print(r.birth.year)  # r.birth是Date的对象  1990
r.birth.get_birth()  # 生日：1990年-12月-30日

d = Dog("旺财", 1989,12,23)
print(d.name)       # 旺财
print(d.birth.day)      # 23
d.birth.get_birth()     # 生日：1989年-12月-23日

加入继承，再次简化

class Animal:
    def __init__(self, name, year, mon, day):
        self.name = name
        self.birth = Date(year, mon, day)

    def eat(self):
        print("eating")

class  People(Animal):
    def __init__(self ,name ,age ,sex ,year ,mon ,day):
        Animal.__init__(self, name, year, mon, day)
        self.age = age
        self.sex = sex
    def talk(self):
        print("talking")

class Dog(Animal):
    def __init__(self, name, year, mon, day):
        Animal.__init__(self, name, year, mon, day)

    def talk(self):
        print("旺旺")

class Date:
    def __init__(self ,year ,mon ,day):
        self.year = year
        self.mon = mon
        self.day = day
    def get_birth(self):
        print("生日：%s年-%s月-%s日" %(self.year, self.mon, self.day))


r = People("bone", 26, "男", 1990, 12, 30)
print(r.name, r.age)  # bone26
print(r.birth.year)  # r.birth是Date的对象  1990
r.birth.get_birth()  # 生日：1990年-12月-30日

d = Dog("旺财", 1989,12,23)
print(d.name)       # 旺财
print(d.birth.day)      # 23
d.birth.get_birth()     # 生日：1989年-12月-23日