python生成器/yield协程/gevent写简单的图片下载器功能示例
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()
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