python提取知乎当前最热的问答内容

#-*- coding: utf-8 -*-
import urllib.request
import re
from _io import open
def yunpan_search():
    url = "https://www.zhihu.com/explore"
    req = urllib.request.Request(url, headers = {
        'Connection': 'Keep-Alive',
        'Accept': 'text/html, application/xhtml+xml, */*',
       'Accept-Language': 'en-US,en;q=0.8,zh-Hans-CN;q=0.5,zh-Hans;q=0.3',
        'User-Agent': 'Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko'
})
    opener = urllib.request.urlopen(req)
    html = opener.read()
    html = html.decode('utf-8')
    rex = '(?<=<textarea class="content hidden">\n).*?(?=<span class="answer-date-link-wrap">)'
    m = re.findall(rex,html,re.S)
    f = open('/root/Desktop/zhihu.txt','w')
    for i in m:
        f.write(i)
        f.write('\n\n')
    f.close()
    print("抓取成功!")
    file = open('/root/Desktop/zhihu.txt','r+')
    fullfile = file.readlines()
    text = []
    p = re.compile(r'\w*', re.L)
    pp = re.compile(r"(&;)*")
    for line in fullfile:
        lines = p.sub('',line)
        liness = pp.sub('',lines)
        text.append(liness)
    file.seek(0)
    file.truncate(0)
    file.writelines(text)
    file.close()
    print("处理成功！")
 
if __name__=='__main__':
    yunpan_search()