26：迭代器和生成器

x='hello'
print(dir(x))
iter_test=x.__iter__()

print(iter_test)
print(iter_test.__next__())
print(iter_test.__next__())
print(iter_test.__next__())
print(iter_test.__next__())
print(iter_test.__next__())
print(iter_test.__next__())

l=[1,2,3]
for i in l:  #i_l=l.__iter_()  i_l.__next__()
    print(i)

index=0
while index < len(l):
    print(l[index])
    index+=1

iter_l=l.__iter__() #遵循迭代器协议，生成可迭代对象
print(iter_l.__next__())
print(iter_l.__next__())

for i in l:
    print(i)

s={1,2,3}

for i in s:
    print(i)
iter_s=s.__iter__()
print(iter_s)
print(iter_s.__next__())
print(iter_s.__next__())
print(iter_s.__next__())
print(iter_s.__next__())

dic={'a':1,'b':2}
iter_d=dic.__iter__()
print(iter_d.__next__())

f=open('test.txt','r+')
# for i in f:
iter_f=f.__iter__()
print(iter_f)
print(iter_f.__next__(),end='')
print(iter_f.__next__(),end='')
l=[1,2,3,4,5]
diedai_l=l.__iter__()
while True:
    try:
        print(diedai_l.__next__())
    except StopIteration:
        # print('迭代完毕了,循环终止了')
        break

l=['die','erzi','sunzi','chongsunzi']

iter_l=l.__iter__()
print(iter_l)
print(iter_l.__next__())
print(iter_l.__next__())
print(iter_l.__next__())
print(iter_l.__next__())
print(iter_l.__next__())
print(next(iter_l)) #next()---->iter_l.__next__()

def test():
    yield 1
    yield 2
    yield 3
g=test()
print('来自函数',g)
print(g.__next__())
print(g.__next__())

三元表达式
name='alex'
name='linhaifeng'
res='SB' if name == 'alex' else '帅哥'
print(res)

列表解析

egg_list=[]
for i in range(10):
    egg_list.append('鸡蛋%s' %i)
print(egg_list)

l=['鸡蛋%s' %i for i in range(10)]
l1=['鸡蛋%s' %i for i in range(10) if i > 5 ]
# l1=['鸡蛋%s' %i for i in range(10) if i > 5 else i] #没有四元表达式
l2=['鸡蛋%s' %i for i in range(10) if i < 5] #没有四元表达式

print(l)
print(l1)
print(l2)

laomuji=('鸡蛋%s' %i for i in range(10)) #生成器表达式
print(laomuji)
print(laomuji.__next__())
print(laomuji.__next__())
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))
print(next(laomuji))

l=[1,2,3,34]
map(func,l)

print(sum(l))
print(sum())
print(sum(i for i in range(10000000000000)))