生成器

#生成器一共两种创建方式
# 1.（x*2 for x in range(5)）
# 2.yield

s = (x*2 for x in range(2))
print(s)

print(next(s))    #等价于print(s.__next__())   in py2: s.next()
print(next(s))
print(next(s))
print(next(s))
print(next(s))
print(next(s))
#for i in range(100):
 #   print(next(s))

s = (x*2 for x in range(100000000000))
print(s)

#print(next(s))    #等价于print(s.__next__())   in py2: s.next()

for i in s: #生成器就是一个可迭代对象（Iterable）
    print(i)




2.

def foo():
    print("ok")
    yield 'tt'
    print('ok2')
    yield 2

g=foo()
# print(g)

for i in foo():
    print(i)