Day4-迭代器生成器

#生成器只有在调用的时候才生成数据, yield 
#只记得住当前的位置
#列表生成器
# a = (i*2 for i in range(10000))
# print(a.__next__())
# for i in range(10):
# a.append(i*2)

# a , = b, a+b的解释如下
# t = (b, a+b)
# a = t[0]
# b = t[1]
#斐波拉契
def fib(max):
 n,a,b = 0,0,1
 while n < max:
 #print(b)
 yield b
 a,b = b,a+b
 #a , = b, a+b的解释如下
 # t = (b, a+b)
 # a = t[0]
 # b = t[1]
 n=n+1
 return "done"
#fib(10)
g = fib(10)
# print(f.__next__())
# print("--------------")
# print(f.__next__())
# print(f.__next__())
# print(f.__next__())
while True:
 try:
 x = next(g)
 print("g:",x)
 except StopIteration as e:
 print("Generator return value:", e.value)
 break