递归实现
>>> >>> def fibonacci(a,b,end): ... if b > end: ... return ... else: ... print b ... (a,b) = (b,a+b) ... fibonacci(a,b,end) ... >>> fibonacci(0,1,10) 1 1 2 3 5 8 >>>
while循环实现
>>> >>> def fibonacci(end): ... a,b = 0,1 ... result = [] ... while b<end: ... result.append(b) ... a,b = b,a+b ... return result ... >>> fibonacci(10) [1, 1, 2, 3, 5, 8] >>>
while+yield实现
>>> >>> def fibonacci(end): ... a,b = 0,1 ... while b<end: ... yield b ... a,b = b,a+b ... >>> for num in fibonacci(10): ... print num ... 1 1 2 3 5 8 >>>
实现迭代器协议 *****
迭代器协议：必须具有 __next__ 和 __iter__ 方法
可迭代对象有 __iter__ 方法，执行__iter__方法得到的就是迭代器# Python3
class Fibonacci(object):
def __init__(self,end):
self._a = 0
self._b = 1
self.end = end
def __next__(self):
if self._b > self.end:
raise StopIteration
self._a,self._b = self._b,self._a+self._b
return self._a
def __iter__(self):
return self
fib = Fibonacci(100)
from collections import Iterator
print(isinstance(fib,Iterator))
for num in fib:
print(num)
######################
True
1
1
2
3
5
8
13
21
34
55
89
