20181009python生成器/yield协程/gevent写简单的下载器

1、生成器：

[code]'''第二种生成器'''

# 函数只有有yield存在就是生成器
def test(i):
while True:
i += 1
res = yield i
print(res)
i += 1
return aa

def main():
t = test(1)  # 创建生成器对象
print(next(t))  # next第一次执行从上到下，yield是终点
print(next(t))
print(t.send(5))

if __name__ == '__main__':
main()

yield协程demo:

[code]def run1():
while True:
print('run1____')
yield

def run2():
while True:
print('run2____')
yield

def main():
while True:
next(run1())
next(run2())

if __name__ == '__main__':
main()

gevent写简单的下载图片

[code]import gevent
import requests,lxml
# from gevent import monkey
# monkey.patch_all()

def get_pic(url, list):
headers = {
'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36'
}
response = requests.get(url, headers=headers)
with open('./pic/'+str(list.pop(0)) + '.png', 'wb') as f:
f.write(response.content)

def get_pic_name_list():

def main():
get_pic_name_list()
list = [x for x in range(9999)]

gevent.joinall([
gevent.spawn(get_pic, 'http://pic8.iqiyipic.com/image/20181008/eb/af/v_116880780_m_601_m11_180_236.jpg', list),
gevent.spawn(get_pic, 'http://pic6.iqiyipic.com/image/20181004/a2/2b/v_112874372_m_601_m15_180_236.jpg', list)
])

if __name__ == '__main__':
main()