1.item系列方法

# class Foo:

#     def __getitem__(self, item):

#         print('getitem',item)

#         return self.__dict__[item]

#

#     def __setitem__(self, key, value):

#         print('setitem')

#         self.__dict__[key]=value

#

#     def __delitem__(self, key):

#         print('delitem')

#         self.__dict__.pop(key)

#

class Foo:

    def  __getitem__(self, item):

        print('getitem',item)

        return self.__dict__[item]

    def __setitem__(self, key, value):

        print('setitem')

        self.__dict__[key] = value

    def __delitem__(self, key):

        print('delitem')

        self.__dict__.pop(key)

f1 = Foo()

print(f1.__dict__)

f1.name = 'egon'

# f1['name'] = 'egon'

f1['age'] = 18

# print(f1.__dict__)

# del f1.name

# print(f1.age)

# del f1['name']

# print(f1.__dict__)

print(f1['age'])

raise  StopAsyncIteration

# f1=Foo()

# print(f1.__dict__)

# # f1.name='egon'  #---->setattr-------->f1.__dict__['name']='egon'

# f1['name']='egon'#--->setitem--------->f1.__dict__['name']='egon'

# f1['age']=18

#

# print('===>',f1.__dict__)

#

# # del f1.name

# # print(f1.__dict__)

# #

# # print(f1.age)

# del f1['name']

# print(f1.__dict__)

#

# print(f1['age'])

# raise S

2.slots属性

class Foo:

    __slots__ = ['name','age']

f1 = Foo()

f1.name = 'egon'

print(f1.name)

# class Foo:

#     __slots__=['name','age']  #{'name':None,'age':None}

    # __slots__='name' #{'name':None,'age':None}

# f1=Foo()

# f1.name='egon'

# print(f1.name)

# f1.age=18  #--->setattr----->f1.__dict__['age']=18

f1.age = 18

# print(f1.__dict__)

print(Foo.__slots__)

print(f1.__slots__)

f1.name = 'egon'

f1.age = 17

print(f1.name)

print(f1.age)

# print(f1.__dict__)

# print(Foo.__slots__)

# print(f1.__slots__)

# f1.name='egon'

# f1.age=17

# print(f1.name)

# print(f1.age)

# f1.gender='male'

# f1.gender = 'male'

f2 = Foo()

print(f2.__slots__)

f2.name = 'alex'

f2.age = 18

print(f2.name)

print(f2.age)

# f2=Foo()

# print(f2.__slots__)

# f2.name='alex'

# f2.age=18

# print(f2.name)

# print(f2.age)

3.内置方法

class Foo:

    x = 1

    def __init__(self,y):

        self.y = y

    def __getattr__(self, item):

        print('------> from getattr:你找的属性不存在')

    def __setattr__(self, key, value):

        print('-----> from setattr')

        self.__dict__[key] = value

    def __delattr__(self, item):

        print('-----> from delattr')

        self.__dict__.pop(item)

f1 = Foo(10)

# class Foo:

#     x=1

#     def __init__(self,y):

#         self.y=y

#

#     def __getattr__(self, item):

#         print('----> from getattr:你找的属性不存在')

#

#

#     def __setattr__(self, key, value):

#         print('----> from setattr')

#         # self.key=value #这就无限递归了,你好好想想

#         # self.__dict__[key]=value #应该使用它

#

#     def __delattr__(self, item):

#         print('----> from delattr')

#         # del self.item #无限递归了

#         self.__dict__.pop(item)

#

#

# f1=Foo(10)

# f1.x

4.描述符

# class Foo:

#     def __get__(self, instance, owner):

#         print('===>get方法')

#     def __set__(self, instance, value):

#         print('===>set方法',instance,value)

#         instance.__dict__['x']=value #b1.__dict__

#     def __delete__(self, instance):

#         print('===>delete方法')

class Foo:

    def __get__(self, instance, owner):

        print('===>get方法')

    def __set__(self, instance, value):

        print('===>set方法',instance,value)

        instance.__dict__['x'] = value

    def __delete__(self, instance):

        print('===>delete方法')

class Bar:

    x = Foo()

    def __init__(self,n):

        self.x = n

b1 = Bar(10)

print(b1.__dict__)

b1.x = 11111111111

print(b1.__dict__)

# class Bar:

#     x=Foo() #在何地？

#     def __init__(self,n):

#         self.x=n #b1.x=10

# b1=Bar(10)

# print(b1.__dict__)

# b1.x=11111111111111111

# print(b1.__dict__)

#

b1.y = 111111111111111111111111

print(b1.__dict__)

print(Bar.__dict__)

# b1.y=11111111111111111111111111111111111111

# print(b1.__dict__)

# print(Bar.__dict__)

b1 = Bar()

b1.x = 1

# del  b1.x

print(b1.x)

#在何时？

# b1=Bar()

# b1.x

#

# b1.x=1

#

# del b1.x

# print(b1.x)

#

# b1.x=1

# print(b1.__dict__)

#

# del b1.x

5.描述符优先级

# class Foo:

#     def  __get__(self, instance, owner):

#         print('===>get方法')

#

#     def __set__(self, instance, value):

#         print('===>set方法',instance,value)

#

#     def __delete__(self, instance):

#         print('===>delete方法')

# class Foo:

#     def __get__(self, instance, owner):

#         print('===>get方法')

#     def __set__(self, instance, value):

#         print('===>set方法',instance,value)

#         # instance.__dict__['x']=value #b1.__dict__

#     def __delete__(self, instance):

#         print('===>delete方法')

#

#

# class Bar:

#     x=Foo() #在何地？

# print(Bar.x)

# Bar.x=1

# print(Bar.__dict__)

# print(Bar.x)

# print(Bar.__dict__)

# b1=Bar()

# b1.x   #get

# b1.x=1 # set

# del b1.x # delete

# b1=Bar()

# Bar.x=111111111111111111111111111111111111111

# b1.x

#

# del Bar.x

# b1.x

class Foo:

    def __get__(self, instance, owner):

        print('===>get方法')

    def __delete__(self, instance):

        print('===>delete方法')

class Bar:

    x = Foo()

    def __getattr__(self, item):

        print('-------->')

b1 = Bar()

# b1.x = 1

print(b1.__dict__)

# class Foo:

#     def __get__(self, instance, owner):

#         print('===>get方法')

#

#

#     # def __delete__(self, instance):

#     #     print('===>delete方法')

#

#

# class Bar:

#     x=Foo() #在何地？

#     def  __getattr__(self, item):

#         print('----->')

#

# b1=Bar()

# b1.x=1

# print(b1.__dict__)

# b1.xxxxxxxxxxxxxxxxxxxxxxx

6.改变对象的字符串显示

# l=list('hello')

#

# print(l)

# file=open('test.txt','w')

# print(file)

# class Foo:

#     def __init__(self,name,age):

#         self.name=name

#         self.age=age

#     def __str__(self):

#         return '名字是%s 年龄是%s' %(self.name,self.age)

#

# f1=Foo('egon',18)

# print(f1) #str(f1)--->f1.__str__()

#

# x=str(f1)

# print(x)

#

# y=f1.__str__()

# print(y)

class Foo:

    def __init__(self,name,age):

        self.name = name

        self.age = age

    def __str__(self):

        return  '折是str'

    def __repr__(self):

        return  '名字是%s 年龄是%s' %(self.name,self.age)

f1 = Foo('as',12)

f1.__repr__()

# class Foo:

#     def __init__(self,name,age):

#         self.name=name

#         self.age=age

#     # def __str__(self):

#     #     return '折是str'

#     def __repr__(self):

#         return '名字是%s 年龄是%s' %(self.name,self.age)

#

# f1=Foo('egon',19)

# #repr(f1)---->f1.__repr__()

# print(f1) #str（f1）---》f1.__str__()------>f1.__repr__()

7.析构方法

# class Foo:

#     def __init__(self,name):

#         self.name=name

#     def __del__(self):

#         print('我执行啦')

#

# f1=Foo('alex')

#

# # del f1    #删除实例会触发__del__

# del f1.name #删除实例的属性不会触发__del__

# print('--------------------->')

#

# #程序运行完毕会自动回收内存，触发__del__

class Foo:

    def __init__(self,name):

        self.name = name

    def __del__(self):

        print('我执行啦')

f1 = Foo('andy')

# del f1.name

8.自定义格式化方法format

# x='{0}{0}{0}'.format('dog')

#

# print(x)

# class Date:

#     def __init__(self,year,mon,day):

#         self.year=year

#         self.mon=mon

#         self.day=day

# d1=Date(2016,12,26)

#

# x='{0.year}{0.mon}{0.day}'.format(d1)

# y='{0.year}:{0.mon}:{0.day}'.format(d1)

# z='{0.mon}-{0.day}-{0.year}'.format(d1)

# print(x)

# print(y)

# print(z)

# x='{0.year}{0.mon}{0.day}'.format(d1)

# y='{0.year}:{0.mon}:{0.day}'

# z='{0.mon}-{0.day}-{0.year}'

# format_dic={

#     'ymd':'{0.year}{0.mon}{0.day}',

#     'm-d-y':'{0.mon}-{0.day}-{0.year}',

#     'y:m:d':'{0.year}:{0.mon}:{0.day}'

# }

format_dic = {

    'ymd':'{0.year}{0.mon}{0.day}',

    'm-d-y':'{0.mon}-{0.day}-{0.year}',

    'y:m:d':'{0.year}:{0.mon}:{0.day}'

}

class Date:

    def  __init__(self,year,mon,day):

        self.year = year

        self.mon = mon

        self.day = day

    def __format__(self, format_spec):

        print('我执行啦')

        print('--->',format_spec)

        if not format_spec or format_spec not in format_dic:

            format_spec = 'ymd'

        fm = format_dic[format_spec]

        return  fm.format(self)

d1 = Date(2016,12,13)

print(format(d1,'ymd'))

print(format(d1,'y:m:d'))

print(format(d1,'m-d-y'))

print(format(d1,'m-d:y'))

# class Date:

#     def __init__(self,year,mon,day):

#         self.year=year

#         self.mon=mon

#         self.day=day

#     def __format__(self, format_spec):

#         print('我执行啦')

#         print('--->',format_spec)

#         if not format_spec or format_spec not in format_dic:

#             format_spec='ymd'

#         fm=format_dic[format_spec]

#         return fm.format(self)

# d1=Date(2016,12,26)

# # format(d1) #d1.__format__()

# # print(format(d1))

# print(format(d1,'ymd'))

# print(format(d1,'y:m:d'))

# print(format(d1,'m-d-y'))

# print(format(d1,'m-d:y'))

# print('===========>',format(d1,'asdfasdfsadfasdfasdfasdfasdfasdfasdfasdfasdfasdfasd'))

print('=============>',format(d1,'assddd'))

9.迭代器协议

# class Foo:

#     def __init__(self,n):

#         self.n=n

#     def __iter__(self):

#         return self

#

#     def __next__(self):

#         if self.n == 13:

#             raise StopIteration('终止了')

#         self.n+=1

#         return self.n

class Foo:

    def __init__(self,n):

        self.n = n

    def __iter__(self):

        return  self

    def __next__(self):

        if self.n == 13:

            raise StopIteration('终止了')

        self.n+=1

        return self.n

f1 = Foo(10)

print(f1.__next__())

print(f1.__next__())

# l=list('hello')

# for i in l:

#     print(i)

# f1=Foo(10)

# # print(f1.__next__())

# # print(f1.__next__())

# # print(f1.__next__())

# # print(f1.__next__())

#

# for i in f1:  # obj=iter(f1)------------>f1.__iter__()

#      print(i)  #obj.__next_()

for i in f1:

    print(i)

10.迭代器协议实现斐波那契数列

# class Fib:

#     def __init__(self):

#         self._a=1

#         self._b=1

#

#     def __iter__(self):

#         return self

#     def __next__(self):

#         if self._a > 100:

#             raise StopIteration('终止了')

#         self._a,self._b=self._b,self._a + self._b

#         return self._a

class Fib:

    def __init__(self):

        self._a = 1

        self._b = 1

    def __iter__(self):

        return  self

    def __next__(self):

        if self._a > 100:

            raise  StopIteration('终止了')

        self._a,self._b=self._b,self._a+self._b

        return self._a

f1 = Fib()

print(next(f1))

print(next(f1))

print(next(f1))

print(next(f1))

print(next(f1))

print(next(f1))

# f1=Fib()

# print(next(f1))

# print(next(f1))

# print(next(f1))

# print(next(f1))

# print(next(f1))

# print('==================================')

# for i in f1:

#     print(i)

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