049乱入：生成器（乱入）

游戏小虾米

Tip：
生成器就是迭代器

一，理论
yield  生成器的标志

二，应用
1 yield
>>> def myGen():
        print('生成器')
        yield 1
        yield 2

       
>>> myG = myGen()
>>> myG
<generator object myGen at 0x02E598A0>
>>> myG()
Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    myG()
TypeError: 'generator' object is not callable
>>> next(myG)
生成器
1
>>> next(myG)
2
>>> next(myG)
Traceback (most recent call last):
  File "<pyshell#10>", line 1, in <module>
    next(myG)
StopIteration

2 斐波那契数列
>>> def libs():
        a = 0
        b = 1
        while True:
                a, b = b, a + b
                yield a

               
>>> for each in libs():
        if each > 100:
                break
        print(each, end = ' ')

       
1 1 2 3 5 8 13 21 34 55 89

3 列表推导式
>>> a = [i for i in range(100) if not(i % 2) and i % 3]
>>>
>>> print(a)
[2, 4, 8, 10, 14, 16, 20, 22, 26, 28, 32, 34, 38, 40, 44, 46, 50, 52, 56, 58, 62, 64, 68, 70, 74, 76, 80, 82, 86, 88, 92, 94, 98]

4 字典推导式
>>> b = {i:i % 2 == 0 for i in range(10)}
>>> b
{0: True, 1: False, 2: True, 3: False, 4: True, 5: False, 6: True, 7: False, 8: True, 9: False}

5集合推导式
>>> c = {i for i in [1,2,3,4,4,1,1,2,3,4,5,7,6]}
>>> c
{1, 2, 3, 4, 5, 6, 7}

6 生成器推导式
>>> d = (i for i in range(10))
>>> for each in d:
        print(each)

       
0
1
2
3
4
5
6
7
8
9
>>> d
<generator object <genexpr> at 0x02E62210>

三，课后练习