【11.6】生成器进阶--yield from

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 
 4 final_result = {}
 5 
 6 
 7 # 子生成器
 8 def sales_sum(pro_name):
 9     total = 0
10     nums = []
11     while True:
12         x = yield
13         print(pro_name+'销量: ', x)
14         if not x:
15             break
16         total += x
17         nums.append(x)
18     return total, nums
19 
20 
21 # 委托生成器
22 def middle(key):
23     while True:
24         final_result[key] = yield from sales_sum(key)
25         print(key+'销量统计完成！！.')
26 
27 
28 # 调用方
29 def main():
30     data_sets = {
31         '小米9': [1200, 1500, 3000],
32         '小米8': [28, 55, 98, 108],
33         '小米5': [200, 560, 778, 70],
34     }
35     for key, data_set in data_sets.items():
36         print('start key:', key)
37         m = middle(key)
38         # 预激middle协程
39         m.send(None)
40         for value in data_set:
41             # 给协程传递每一组的值
42             m.send(value)
43         # 结束
44         m.send(None)
45     print('final_result:', final_result)
46 
47 
48 if __name__ == '__main__':
49     main()

start key: 小米9
小米9销量:  1200
小米9销量:  1500
小米9销量:  3000
小米9销量:  None
小米9销量统计完成！！.
start key: 小米8
小米8销量:  28
小米8销量:  55
小米8销量:  98
小米8销量:  108
小米8销量:  None
小米8销量统计完成！！.
start key: 小米5
小米5销量:  200
小米5销量:  560
小米5销量:  778
小米5销量:  70
小米5销量:  None
小米5销量统计完成！！.
final_result: {'小米9': (5700, [1200, 1500, 3000]), '小米8': (289, [28, 55, 98, 108]), '小米5': (1608, [200, 560, 778, 70])}

yield from最主要的用法

1 # main调用方、g1（委托生成器）、gen 子生成器
2 # yield from会在调用方与子生成器之间建立一个双向通道
3 def g1(gen):
4     yield from gen
5 
6 
7 def main():
8     g = g1()
9     g.send(None)

yield from 处理了StopIteration的异常

yield from 其他用法

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 # python3.3新加了yield from语法
 4 
 5 
 6 from itertools import chain
 7 
 8 
 9 my_list = [1, 2, 3]
10 my_dict = {
11     'zy1': 'http://projectsedu.com',
12     'zy2': 'http://www.imooc.com'
13 }
14 
15 
16 # yield from iterable（可迭代对象）
17 def my_chain(*args, **kwargs):
18     for my_iterable in args:
19         yield from my_iterable
20         # for value in my_iterable:
21         #     yield value
22 
23 
24 for value in my_chain(my_list, my_dict, range(5, 10)):
25     print(value)

【11.6】生成器进阶--yield from

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