Python3基础 yield send 获得生成器后，需要先启动一次
- Python : 3.7.3
- OS : Ubuntu 18.04.2 LTS
- IDE : pycharm-community-2019.1.3
- Conda : 4.7.5
- typesetting : Markdown
code
"""
@Author : 行初心
@Date : 2019/7/6
@Blog : www.cnblogs.com/xingchuxin
@Gitee : gitee.com/zhichengjiu
"""
def yield_test():
# next() 遇到yield会停止，保存数据并返回后面的数值
# send_value默认为None
a = 1
send_value = yield a + 1
print(send_value)
send_value = yield a + 1
print(send_value)
def main():
# 获得生成器
generator = yield_test()
# 启动 - 第一种方式
print(id(generator), generator.__next__())
# 想理解好 send 的功能，建议使用 Debug - Step Into(F7)。一步一步地跟下来
print(generator.send("hello"))
print("---")
# 获得生成器
generator = yield_test()
# 启动 - 第二种方式
print(id(generator), generator.send(None))
print(generator.send("world"))
print("---")
if __name__ == '__main__':
main()
result
/home/coder/anaconda3/envs/py37/bin/python /home/coder/PycharmProjects/NumericalComputation/demo.py
140581898176336 2
hello
2
---
140581898176456 2
world
2
---
Process finished with exit code 0
source_code
class Generator(Iterator[_T_co], Generic[_T_co, _T_contra, _V_co]):
@abstractmethod
def __next__(self) -> _T_co: ...
@abstractmethod
def send(self, value: _T_contra) -> _T_co: ...
@abstractmethod
def throw(self, typ: Type[BaseException], val: Optional[BaseException] = ...,
tb: Optional[TracebackType] = ...) -> _T_co: ...
@abstractmethod
def close(self) -> None: ...
@abstractmethod
def __iter__(self) -> Generator[_T_co, _T_contra, _V_co]: ...
@property
def gi_code(self) -> CodeType: ...
@property
def gi_frame(self) -> FrameType: ...
@property
def gi_running(self) -> bool: ...
@property
def gi_yieldfrom(self) -> Optional[Generator]: ...
# TODO: Several types should only be defined if sys.python_version >= (3, 5):
# Awaitable, AsyncIterator, AsyncIterable, Coroutine, Collection.
# See https: //github.com/python/typeshed/issues/655 for why this is not easy.
more_knowledge
code
"""
@Author : 行初心
@Date : 2019/7/6
@Blog : www.cnblogs.com/xingchuxin
@Gitee : gitee.com/zhichengjiu
"""
def yield_test():
a = 1
send_value = yield a + 1
print(send_value)
def main():
# 获得生成器
generator = yield_test()
# 直接用send("hello world")
generator.send("hello world")
if __name__ == '__main__':
main()
result
/home/coder/anaconda3/envs/py37/bin/python /home/coder/PycharmProjects/NumericalComputation/demo.py
Traceback (most recent call last):
File "/home/coder/PycharmProjects/NumericalComputation/demo.py", line 29, in <module>
main()
File "/home/coder/PycharmProjects/NumericalComputation/demo.py", line 25, in main
generator.send("hello world")
TypeError: can't send non-None value to a just-started generator
Process finished with exit code 1
reference
- https://www.cnblogs.com/xhcdream/p/8304953.html
resource
- [文档 - English] docs.python.org/3
- [文档 - 中文] docs.python.org/zh-cn/3
- [规范] www.python.org/dev/peps/pep-0008
- [规范] zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_language_rules
- [源码] www.python.org/downloads/source
- [ PEP ] www.python.org/dev/peps
- [平台] www.cnblogs.com
- [平台] gitee.com
Python具有开源、跨平台、解释型、交互式等特性，值得学习。
Python的设计哲学：优雅，明确，简单。提倡用一种方法，最好是只有一种方法来做一件事。
代码的书写要遵守规范，这样有助于沟通和理解。
每种语言都有独特的思想，初学者需要转变思维、踏实践行、坚持积累。
1、《SOA In the real world》第一章译稿（含下载）
2、python中的变量
3、使用InfluxDB+cAdvisor+Grafana配置Docker监控
4、MEF
5、python命令方式和关键字