类关系/self/特殊成员

1.依赖关系
　　在方法中引入另一个类的对象
2.关联关系、聚合关系、组合关系

#废话少说 直接上代码===>选课系统

 # coding:utf-8

 class Student(object):
     def __init__(self, sid, name, addr):
         self.sid = sid
         self.name = name
         self.addr = addr
         self.course = []

     def get_info(self):
         for el in self.course:
             print(el.cid, el.title, el.teacher.tid,\
                   el.teacher.name,el.teacher.phone)

     def add_course(self, course):
         self.course.append(course)

 class Course(object):
     def __init__(self, cid, title):
         self.cid = cid
         self.title = title
         self.course_list = []
         self.teacher = ''

     def get_info(self, course):
         pass

     def setting_teacher(self, teacher):
         self.teacher = teacher

 class Teacher(object):
     def __init__(self, tid, name, phone):
         self.tid = tid
         self.name = name
         self.phone = phone

 t1 = Teacher(11, "张三", 1815786)
 t2 = Teacher(22, "李四", 10086)

 c1 = Course(1, "python1")
 c1.setting_teacher(t1)
 c2 = Course(2, "python2")
 c2.setting_teacher(t2)
 c3 = Course(3, "python3")
 c3.setting_teacher(t1)
 s1 = Student(111, "alex", "北京")
 s1.add_course(c1)
 s1.add_course(c2)
 s1.add_course(c3)
 s1.get_info()

3.继承关系，实现关系
　　#可哈希:内部是否有哈希算法
　　__hash__
　　默认的类和对象都是可哈希的
　　self就是你访问方法的那个对象. 先找自己, 然后在找父类的.

废话少说 上代码

 class Base:
     def __init__(self, num):
         self.num = num

     def func1(self):
         print(self.num)
         self.func2()

     def func2(self):
         print(111, self.num)

 class Foo(Base):
     def func2(self):
         print(222, self.num)

 # Base(1) 1 111 1
 # Base(2) 2 111 2
 # Foo(3)  3 222 3
 # 这里面注意换行
 lst = [Base(1), Base(2), Foo(3)]
 for obj in lst:
     obj.func1()  # 那笔来吧. 好好算.

4.特殊成员(__init__())
　　即带双下划线的
　　1.类名() __init__构造方法
　　2.对象() __call__() python 特有的