'''斐波那契数列专题 使用现在学习的各种方法'''
# 数组实现
my_list = [1, 1]
for i in range(2, 10):
my_list.append(my_list[i-2]+my_list[i-1])
print('数组 ', my_list)
# 交换变量
a = b = 1
for i in range(10-2):
a, b = b, a+b
print('交换变量 ', b)
# 递归与尾递归
def fbi(n):
if n < 3:
return 1
else:
return fbi(n-2)+fbi(n-1)
def xfbi(n, i, j):
if n < 3:
return j
else:
return xfbi(n-1, j, i+j)
print('递归 ', fbi(10))
print('尾递归 ', xfbi(10, 1, 1))
# 迭代器
class MylistIter(object):
def __init__(self, n):
self.n = n
self.i = 1
self.j = 1
def __next__(self):
if self.n > 0:
v = self.i
self.i, self.j = self.j, self.i + self.j
self.n -= 1
return v
else:
raise StopIteration
def __iter__(self):
return self
class Mylist(object):
def __init__(self, n):
self.n = n
def __iter__(self):
return MylistIter(self.n)
for i in Mylist(10):
pass
print('迭代器1 ', i)
class MylistIter2(object):
def __init__(self):
self.i = 1
self.j = 1
def __next__(self):
v = self.i
self.i, self.j = self.j, self.i + self.j
return v
def __iter__(self):
return self
i = 0
myiter = MylistIter2()
while i < 10:
a = next(myiter)
i += 1
print('迭代器2 ', a)
# 生成器
def fun():
i,j = 1, 1
for n in range(100):
yield i
i, j = j, j+i
f = fun()
for i in range(10):
b = next(f)
print('生成器 ', b)
