异步IO和协程

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @File  : 多任务yield-demo2.py
# @Author: Liugp
# @Date  : 2019/6/2
# @Desc  :

def gen_func():
    # 1.可以产出值；2.可以接收值，调用方法传进来的值
    try:
        yield "http://www.baidu.com"
    except Exception:
        pass
    yield 2
    yield 3
    return "bobby"

# 1.生成器不仅可以产出值，还可以接收值

if __name__ == "__main__":
    gen = gen_func()
    print(next(gen))
    gen.throw(Exception,"download error")
    print(next(gen))
    gen.throw(Exception, "download error")

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @File  : gen_close.py
# @Author: Liugp
# @Date  : 2019/6/2
# @Desc  :
def gen_func():
    # 1.可以产出值；2.可以接收值，调用方法传进来的值
    yield "http://www.baidu.com"
    yield 2
    yield 3
    return "bobby"

# 1.生成器不仅可以产出值，还可以接收值

if __name__ == "__main__":
    gen = gen_func()
    print(next(gen))
    gen.close()
    print(‘bobby‘)

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @File  : gen_to_coroutine.py.py
# @Author: Liugp
# @Date  : 2019/6/2
# @Desc  :
# 生成器是可以暂停的函数
import inspect
def gen_func():
    value = yield 1
    return "bobby"



if __name__ == "__main__":
    gen = gen_func()
    print(inspect.getgeneratorstate(gen))
    next(gen)
    print(inspect.getgeneratorstate(gen))
    try:
        next(gen)
    except StopIteration:
        pass
    print(inspect.getgeneratorstate(gen))

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @File  : yield_from_test.py
# @Author: Liugp
# @Date  : 2019/6/2
# @Desc  :
from itertools import chain

my_list = [1,2,3]
my_dict = {
    ‘bobby1‘:‘http://www.baidu.com‘,
    ‘bobby2‘:‘http://www.taobao.com‘
}

def my_chain(*args,**kwargs):
    for my_iterable in args:
        yield from my_iterable
        # for value in my_iterable:
        #     yield value

for value in my_chain(my_list,my_dict,range(5,10)):
    print(value)


def g1(iterable):
    yield from iterable

def main():
    g = g1()
    g.send(None)

#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