319 lines
6.8 KiB
Markdown
319 lines
6.8 KiB
Markdown
# 类空间与类之间的关系
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## 类的空间问题
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### 添加对象属性
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```python
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class A:
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def __init__(self,name):
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self.name = name
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def func(self,sex):
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self.sex = sex
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```
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在类外部添加
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```python
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class A:
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def __init__(self,name):
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self.name = name
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def func(self,sex):
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self.sex = sexa
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obj = A('zhangsan')
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obj.age = 18
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print(obj.__dict__)
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```
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类的内部添加
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```python
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class A:
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def __init__(self,name):
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self.name = name
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def func(self,sex):
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self.sex = sex
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obj = A('zhangsan')
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obj.func('男')
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print(obj.__dict__)
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```
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**总结：对象的属性不仅可以在`__init__` 里面添加，还可以在类的其他方法或者类的外面添加。**
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### 添加类的静态属性
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```python
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class A:
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def __init__(self,name):
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self.name = name
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def func(self,sex):
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self.sex = sex
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def func1(self):
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A.bbb = self
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A.aaa = 'test' # 类的外部添加
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print(A.__dict__)
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A.func1('123') # 类的内部添加
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print(A.__dict__)
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```
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**总结：类的属性不仅可以在类内部添加，还可以在类的外部添加**
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## 对象如何找到类的属性
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对象空间
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1. 产生这个对象空间，并有一个类对象指针
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2. 执行`__init__`方法，给对象封装属性
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对象查找属性的顺序：先从对象空间找 ------> 类空间找 ------> 父类空间找 ------->.....
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类名查找属性的顺序：先从本类空间找 -------> 父类空间找--------> ........
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上面的顺序都是单向不可逆，类名不可能找到对象的属性。
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## 类与类之间的关系
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类与类中存在以下关系:
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1. 依赖关系
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2. 关联关系
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3. 组合关系
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4. 聚合关系
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5. 实现关系
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6. 继承关系(类的三大特性之一：继承。)
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### 依赖关系
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例：将大象装进冰箱，需要两个类, ⼀个是⼤象类, ⼀个是冰箱类
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```python
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class Elphant:
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def __init__(self,name):
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self.name = name
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def open(self):
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'''
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开门
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'''
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pass
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def close(self):
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'''
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关门
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'''
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pass
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class Refrigerator:
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def open_door(self):
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print('冰箱门打开了')
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def open_door(self):
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print('冰箱门关上了')
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```
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将大象类和冰箱类进行依赖
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```python
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class Elphant:
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def __init__(self,name):
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self.name = name
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def open(self,obj1):
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'''
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开门
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'''
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print(self.name,'要开门了')
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obj1.open_door()
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def close(self):
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'''
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关门
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'''
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pass
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class Refrigerator:
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def open_door(self):
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print('冰箱门打开了')
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def close_door(self):
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print('冰箱门关上了')
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elphant1 = Elphant('大象')
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haier = Refrigerator()
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elphant1.open(haier)
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```
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### 关联,聚合,组合关系
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其实这三个在代码上写法是⼀样的. 但是, 从含义上是不⼀样的.
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1. 关联关系. 两种事物必须是互相关联的. 但是在某些特殊情况下是可以更改和更换的.
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2. 聚合关系. 属于关联关系中的⼀种特例. 侧重点是xxx和xxx聚合成xxx. 各⾃有各⾃的声明周期. 比如电脑. 电脑⾥有CPU, 硬盘, 内存等等. 电脑挂了. CPU还是好的. 还是完整的个体
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3. 组合关系. 属于关联关系中的⼀种特例. 写法上差不多. 组合关系比聚合还要紧密. 比如⼈的⼤脑, ⼼脏, 各个器官. 这些器官组合成⼀个⼈. 这时. ⼈如果挂了. 其他的东⻄也跟着挂了
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**关联关系**
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```python
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class Boy:
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def __init__(self, name, girlFirend=None):
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self.name = name
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self.girlFriend = girlFirend
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def have_a_dinner(self):
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if self.girlFriend:
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print('%s 和 %s 一起晚饭' % (self.name, self.girlFriend.name))
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else:
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print('单身狗，吃什么饭')
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class Girl:
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def __init__(self, name):
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self.name = name
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b = Boy('张三')
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b.have_a_dinner()
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b.girlFriend = Girl('如花')
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b.have_a_dinner()
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gg = Girl('花花')
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bb = Boy('李四', gg)
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bb.have_a_dinner()
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```
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注意. 此时Boy和Girl两个类之间就是关联关系. 两个类的对象紧密联系着. 其中⼀个没有了. 另⼀个就孤单的不得了. 关联关系, 其实就是 我需要你. 你也属于我
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学校和老师之间的关系
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```python
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class School:
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def __init__(self,name,address):
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self.name = name
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self.address = address
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class Teacher:
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def __init__(self,name,school):
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self.name = name
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self.school = school
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s1 = School('北京校区','北京')
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s2 = School('上海校区','上海')
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s3 = School('深圳校区','深圳')
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t1 = Teacher('张老师',s1)
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t2 = Teacher('李老师',s2)
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t3 = Teacher('王老师',s3)
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print(t1.school.name)
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print(t2.school.name)
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print(t3.school.name)
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```
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但是学校也是依赖于老师的，所以老师学校应该互相依赖。
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```python
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class School:
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def __init__(self, name, address):
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self.name = name
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self.address = address
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self.teacher_list = []
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def append_teacher(self, teacher):
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self.teacher_list.append(teacher)
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class Teacher:
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def __init__(self, name, school):
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self.name = name
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self.school = school
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school.append_teacher(self)
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s1 = School('北京校区', '北京')
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s2 = School('上海校区', '上海')
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s3 = School('深圳校区', '深圳')
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t1 = Teacher('张老师', s1)
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t2 = Teacher('李老师', s1)
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t3 = Teacher('王老师', s3)
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print(s1.teacher_list)
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print(f"{s1.name} 校区，老师的名单如下：")
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for teacher in s1.teacher_list:
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print(teacher.name)
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```
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**组合：将一个类的对象封装到另一个类的对象的属性中，就叫组合。**
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例：设计一个游戏，让游戏里面的人物互殴
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```python
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class Gamerole:
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def __init__(self,name,ad,hp):
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self.name = name
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self.ad = ad
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self.hp = hp
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def attack(self,p1):
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p1.hp -= self.ad
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print('%s攻击%s,%s掉了%s血,还剩%s'%(self.name,p1.name,p1.name,self.ad,p1.hp))
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man = Gamerole('人',10,100)
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dog = Gamerole('狗',50,100)
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dog.attack(man)
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man.attack(dog)
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```
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加上一个武器类，让人使用武器攻击
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```python
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class Gamerole:
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def __init__(self,name,ad,hp):
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self.name = name
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self.ad = ad
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self.hp = hp
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def attack(self,p1):
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p1.hp -= self.ad
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print('%s攻击%s,%s掉了%s血,还剩%s'%(self.name,p1.name,p1.name,self.ad,p1.hp))
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def equip_weapon(self,wea):
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self.wea = wea
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class Weapon:
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def __init__(self,name,ad):
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self.name = name
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self.ad = ad
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def weapon_attack(self,p1,p2):
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p2.hp = p2.hp - self.ad - p1.ad
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print('%s利用%s攻击了%s，%s还剩%s血'%(p1.name,self.name,p2.name,p2.name,p2.hp))
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man = Gamerole('人',10,100)
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dog = Gamerole('狗',50,100)
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stick = Weapon('木棍',40)
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man.equip_weapon(stick)
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man.wea.weapon_attack(man,dog)
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# 人利用木棍攻击了狗，狗还剩50血
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``` |