面向对象三 组合 特殊成员

一.组合

class Foo(object):
    def __init__(self,age):
        self.age = age
    def display(self):
        print(self.age)
data_list = [Foo(8),Foo(9)]
for item in data_list:
    print(item.age,item.display())
#结果:8   8  None   9   9   None

class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
class RoleConfig(StarkConfig):
    def changelist(self,request):
        print("666")
config_obj_list = [StarkConfig(1),StarkConfig(2),RoleConfig(3)]
for item in config_obj_list:
    print(item.num)

class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
class RoleConfig(StarkConfig):
    pass
config_obj_list=[StarkConfig(1),StarkConfig(2),RoleConfig(3)]
for item in config_obj_list:
    item.changelist(168)
#结果:1 168 2 168 3 168

class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
class RoleConfig(StarkConfig):
    def changelist(self,request):
        print(666,self.num)
config_obj_list=[StarkConfig(1),StarkConfig(2),RoleConfig(3)]
for item in config_obj_list:
    item.changelist(168)
#结果: 1 168  2 168  666 3

实例

class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
    def run(self):
        self.changelist(999)
class RoleConfig(StarkConfig):
    def changelist(self,request):
        print(666,self.num)
class AdminSite(object):
    def __init__(self):
        self._registry = {}
    def register(self,k,v):
        self._registry[k] = v
site = AdminSite()
print(len(site._registry))
site.register("range",666)
site.register("shilei",438)
print(len(site._registry))
#结果: 0  2

class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
    def run(self):
        self.changelist(999)
class RoleConfig(StarkConfig):
    def changelist(self,request):
        print(666,self.num)
class AdminSite(object):
    def __init__(self):
        self._registry = {}
    def register(self,k,v):
        self._registry[k] = v
site = AdminSite()
# print(len(site._registry))
# site.register("range",666)
# site.register("shilei",438)
# print(len(site._registry))
site.register("lyd",StarkConfig(19))
site.register("yjl",StarkConfig(20))
site.register("fgz",RoleConfig(33))
print(len(site._registry))
for k,row in site._registry.items():
    row.changelist(5)
#结果:  19 5  20 5  666 33

class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
    def run(self):
        self.changelist(999)
class RoleConfig(StarkConfig):
    def changelist(self,request):
        print(666,self.num)
class AdminSite(object):
    def __init__(self):
        self._registry = {}
    def register(self,k,v):
        self._registry[k] = v
site = AdminSite()
site.register("lyd",StarkConfig(19))
site.register("yjl",StarkConfig(20))
site.register("fgz",RoleConfig(33))
print(len(site._registry))
for k,row in site._registry.items():
    row.run()
#结果: 19 999  20 999  666 33

class Userlnfo(object):
    pass
class Department(object):
    pass
class StarkConfig(object):
    def __init__(self,num):
        self.num = num
    def changelist(self,request):
        print(self.num,request)
    def run(self):
        self.changelist(999)
class RoleConfig(StarkConfig):
    def changelist(self,request):
        print(666,self.num)
class AdminSite(object):
    def __init__(self):
        self._registry = {}
    def register(self,k,v):
        self._registry[k] = v(k)
site = AdminSite()
site.register(Userlnfo,StarkConfig)
site.register(Department,StarkConfig)
print(len(site._registry))
for k,row in site._registry.items():
    row.run()
#结果:  Userlnfo类 999
#      Department类 999

总结:

　　1.对象中封装了什么

　　2.self 到底是谁

二.主动调用其它类的成员

　　方式一:

class Base:
    def f1(self):
        print("5个功能")
class Foo:
    def f1(self):
        print("3个功能")
        Base.f1(self)
obj = Foo()
obj.f1()

总结:

　　Base.实例方法(自己传self)

　　与继承无关

　　方式二:按照类的继承顺序,找下一个

class Foo:
    def f1(self):
        super().f1()
        print("3个功能")
class Bar:
    def f1(self):
        print("5个功能")
class lnfo(Foo,Bar):
    pass
obj = lnfo()
obj.f1()
class Foo:
    def f1(self):
        print("5个功能")
class Bar(Foo):
    def f1(self):
        super().f1()
        print("3个功能")
obj = Bar()
obj.f1()

三.特殊成员

1. __doc__

　　表示类的描述信息

class Foo:
    """ 描述类信息，这是用于看片的神奇 """

    def func(self):
        pass

print Foo.__doc__
#输出：类的描述信息

2. 类名()   自动执行__init__ # 初始化方法

　　初始化数据，通过类创建对象时，自动触发执行。

class Foo:

    def __init__(self, name):
        self.name = name
        self.age = 18


obj = Foo('wupeiqi') 
# 自动执行类中的 __init__ 方法

3.对象()  自动执行__call__

class  Foo(object):
     def __call__(self,*args,**kwargs):
          print(520,args,kwargs)
          return 
obj  = Foo()
obj(3,6,5,k1= 582)        
#11111 (6, 4, 2) {'k1': 456}

4. 对象["xx"]   自动执行 __getitem__

class Foo (object):
　　def  __getijtem__(self,item): 
   　　print(item): 
　　　　return "ss"
obj = Foo() 
ret  = obj[ "wang"]                                                                                    print(ret)    
 #   wang    ss

5.对象["ss"] = 11    自动执行__setitem__

class Foo(object)
    def  _getitem__(self,key,value):
    　　print(key,value,520)
obj = Foo()
obj["shuzi"] = 666      
#  shuzi   666   520

6.del   对象[xx]       自动执行__delitem__

class  Foo (object):
    def __delitem__(self,key):
   　　 print(key)
obj = Foo()
del  obj["wang"]  
#   wang

7.对象+对象      自动执行__add__

class  Foo(object)
    def __init__(self,s1,s2):
    　　self.s1 = s1
    　　self.s2 = s2
    def__add__(self,other):
        return  self.s1 + other.s2
obj1 = Foo(1,2)
obj2 = Foo(88,99)
ret = obj1 + obj2
print(ret)   
#  100

8. with 对象     自动执行__enter__/ __exit__

class  Foo(object):
     def __init__(self,s1,s2):
         self.s1 = s1
         self.s2 = s2
     def __enter__(self):
         print("520")
         return  999
     def __exit__(self,exc_type,exc_val,exc_tb):
         print("251")
obj = Foo(1,2)
with obj as f:
   print(f)
   print("代码块")  
#   520   999    代码块   251

  9. __new__ 构造方法

class Foo(object):
    def __init__(self, a1, a2):     # 初始化方法
        """
        为空对象进行数据初始化
        :param a1:
        :param a2:
        """
        self.a1 = a1
        self.a2 = a2

    def __new__(cls, *args, **kwargs): # 构造方法
        """
        创建一个空对象
        :param args:
        :param kwargs:
        :return:
        """
        return object.__new__(cls)

10. __dict__   类或对象中的所有成员

　　类的普通字段属于对象；类中的静态字段和方法等属于类，

class Province:

    country = 'China'

    def __init__(self, name, count):
        self.name = name
        self.count = count

    def func(self, *args, **kwargs):
        print 'func'

# 获取类的成员，即：静态字段、方法、
print Province.__dict__
# 输出：{'country': 'China', '__module__': '__main__', 'func': <function func at 0x10be30f50>, '__init__': <function __init__ at 0x10be30ed8>, '__doc__': None}

obj1 = Province('HeBei',10000)
print obj1.__dict__
# 获取 对象obj1 的成员
# 输出：{'count': 10000, 'name': 'HeBei'}

obj2 = Province('HeNan', 3888)
print obj2.__dict__
# 获取 对象obj1 的成员
# 输出：{'count': 3888, 'name': 'HeNan'}

11. __iter__ 

用于迭代器，之所以列表、字典、元组可以进行for循环，是因为类型内部定义了 __iter__ 

class Foo(object):

    def __init__(self, sq):
        self.sq = sq

    def __iter__(self):
        return iter(self.sq)

obj = Foo([11,22,33,44])

for i in obj:
    print i

创建类就可以有两种方式：

　　a). 普通方式

class Foo(object):
 
    def func(self):
        print 'hello wupeiqi'

　　b).特殊方式（type类的构造函数）

def func(self):
    print 'hello wupeiqi'
 
Foo = type('Foo',(object,), {'func': func})
#type第一个参数：类名
#type第二个参数：当前类的基类
#type第三个参数：类的成员