十七. __next__和__iter__实现迭代器协议
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一. __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
class Da(object): def __init__(self,num): self.num=num def __iter__(self): return self def __next__(self): if self.num>=88: raise StopIteration ("你有一场") self.num+=1 return self.num aa=Da(1) # for i in aa: # print(i) bb=aa.__iter__() print(bb.__next__()) print(bb.__next__())
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 Range: def __init__(self,n,stop,step): self.n=n self.stop=stop self.step=step def __next__(self): if self.n >= self.stop: raise StopIteration x=self.n self.n+=self.step return x def __iter__(self): return self for i in Range(1,7,3): # print(i) 练习:简单模拟range,加上步长
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
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