对yield的初步理解

 1 def go():
 2     while True:
 3         data = 1
 4         r = yield data  # data是返回值，r是接收值
 5         print("data", data)
 6         print("A1", r)
 7         data += 1
 8 
 9         r = yield data
10         print("data",data)
11         r += r
12         print("A2", r)
13         data += 1
14 
15         r = yield data
16         print("data",data)
17         print("A3", r)
18         # 运行时此后若找不到下一个yield，则会报错StopIteration
19 
20 my = go()
21 print("my", my)
22 print("None", my.send(None))
23 print(my.send("1"))
24 print(my.send("2"))
25 print(my.send("3"))