python基础----__next__和__iter__实现迭代器协议

#_*_coding:utf-8_*_
__author__ = 'Linhaifeng'
class Foo:
    def __init__(self,x):
        self.x=x

    def __iter__(self):
        return self

    def __next__(self):
        n=self.x
        self.x+=1
        return self.x

f=Foo(3)
for i in f:
    print(i)

简单示范

简单示范

class Foo:
    def __init__(self,start,stop):
        self.num=start
        self.stop=stop
    def __iter__(self):
        return self
    def __next__(self):
        if self.num >= self.stop:
            raise StopIteration
        n=self.num
        self.num+=1
        return n

f=Foo(1,5)
from collections import Iterable,Iterator
print(isinstance(f,Iterator))

for i in Foo(1,5):
    print(i)

class Fib:
    def __init__(self):
        self._a=0
        self._b=1

    def __iter__(self):
        return self

    def __next__(self):
        self._a,self._b=self._b,self._a + self._b
        return self._a

f1=Fib()

print(f1.__next__())
print(next(f1))
print(next(f1))

for i in f1:
    if i > 100:
        break
    print('%s ' %i,end='')

斐波那契数列

斐波那契数列

笔记：

 from collections import Iterable,Iterator
 class Foo:
     def __init__(self,start):
         self.start=start

     def __iter__(self):
         return self

     def __next__(self):
         return 'aSB'

 f=Foo(0)
 f.__iter__()
 f.__next__()

 print(isinstance(f,Iterable))
 print(isinstance(f,Iterator))

 print(next(f)) #f.__next__()
 print(next(f)) #f.__next__()
 print(next(f)) #f.__next__()

 for i in f: # res=f.__iter__() #next(res)
     print(i)

 from collections import Iterable,Iterator
 class Foo:
     def __init__(self,start):
         self.start=start

     def __iter__(self):
         return self

     def __next__(self):
         if self.start > 10:
             raise StopIteration
         n=self.start
         self.start+=1
         return n

 f=Foo(0)

 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))
 print(next(f))

 for i in f:
     print('====>',i)

 class Range:
     ''
     def __init__(self,start,end):
         self.start=start
         self.end=end

     def __iter__(self):
         return self

     def __next__(self):
         if self.start == self.end:
             raise StopIteration
         n=self.start
         self.start+=1
         return n

 for i in Range(0,3):
     print(i)

 print(Range.__doc__)

 class Foo:
     '我是描述信息'
     pass

 class Bar(Foo):
     pass
 print(Bar.__doc__) #该属性无法继承给子类

 b=Bar()
 print(b.__class__)
 print(b.__module__)
 print(Foo.__module__)
 print(Foo.__class__) #?

笔记