python yeild: send, close, throw

def gen_func():
    #1. 可以产出值， 2. 可以接收值(调用方传递进来的值)
    html = yield 1
    print(html)
    yield 2
    yield 3
    return "bobby"

#1. 生成器不只可以产出值，还可以接收值
if __name__ == "__main__":
    gen = gen_func()
    #在调用send发送非none值之前，我们必须启动一次生成器， 方式有两种1. gen.send(None), 2. next(gen)
    url = gen.send(None)
    #download url
    html = "bobby"
    print(gen.send(html)) #send方法可以传递值进入生成器内部，同时还可以重启生成器执行到下一个yield位置
    print(gen.send(html))

def gen_func():
    yield "http://projectsedu.com"
    yield 2
    yield 3
    return "bobby"

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

def gen_func():
    #1. 可以产出值， 2. 可以接收值(调用方传递进来的值)
    try:
        yield "http://projectsedu.com"
    except Exception as e:
        pass
    try:
        yield 2
    except Exception as e:
        pass
    yield 3
    return "bobby"

if __name__ == "__main__":
    gen = gen_func()
    print(next(gen))
    gen.throw(Exception, "download error")
    print(next(gen))
    gen.throw(Exception, "download error1")