本文实例讲述了python生成器/yield协程/gevent写简单的图片下载器功能。分享给大家供大家参
本文实例讲述了python生成器/yield协程/gevent写简单的图片下载器功能。分享给大家供大家参考，具体如下：
1、生成器：
'''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 res
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()
运行结果：
2 None 4 5 6
2、yield协程demo:
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()
3、gevent写简单的下载图片
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()