Python day14迭代器，三元表达式，列表解析以及生成器表达式

1.迭代器

str=['sds','ccc','dw']
lit_1=str.__iter__()#获取迭代器
print(lit_1.__next__())#打印下一个值

# 用while做for的事情
while True:
    try:
        print(lit_1.__next__())
    except StopIteration:
        break

2.三元表达式

name='dn'
name='4' if name=='dn' else '3'

3.列表解析

li=[]
for i in range(10):
    li.append(i)
print(li)

ri=[i for i in range(10)]
print(ri)
pe=['person%d'%i for i in range(10)]
print(pe)

4.生成器表达式

pe=('person%d'%i for i in range(10))
print(next(pe))

5.生成器函数

def test():
    yield 1
    yield 2
    yield 3
    yield 4

r=test()
print(r.__next__())
print(r.__next__())
print(r.__next__())
print(r.__next__())

#yield的案例
def get_infor():
    with open('1.txt','r') as f:
       for i in f:
           yield i
a=get_infor()
print(a.__next__().rstrip())
print(a.__next__().rstrip())
print(a.__next__().rstrip())