urllib_百度的百度一下

#获取网页源码
#解析服务器响应文件
#打印
import urllib.request
url='https://www.baidu.com'
headers={
    'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16299'
}
request=urllib.request.Request(url=url,headers=headers)
response=urllib.request.urlopen(request)
content=response.read().decode('utf-8')
#print(content)
from lxml import etree
html=etree.HTML(content)
#xpath返回值是一个列表
result=html.xpath('//input[@id="su"]/@value')[0]
print(result)