python爬虫教程之bs4解析和xpath解析详解

fp = open( './test.html','r',encoding='utf-8')
soup=BeautifulSoup(fp,'lxml')

page_text =response.text
soup=BeatifulSoup(page_text,'lxml')

soup对象:

<div class="tang">
    <ul>
        <li><a href="Http://www.baidu.com" rel="external nofollow"  title= "ging">清明时节雨纷纷,路上行人欲断魂,借问酒家何处有,牧童遥指杏花村</a></1i>
        <li><a href="http://www.163.com" rel="external nofollow"  title="qin">秦时明月汉时关，万里长征人未还,但使龙城飞将在，不教胡马度阴山</a></1i>
        <li><a href=" http://ww.126.com" rel="external nofollow" alt="qi ">歧王宅里寻常见，崔九堂前几度闻，正是江南好风景,落花时节又逢君</a></li>
        <li><a href="http: //www.sina.com" rel="external nofollow"  class="du">杜甫</a></li>
        <li><a href="http://www.dudu.com" rel="external nofollow"  class="du">杜牧</a></li>
        <li><b>杜小月</b></li>
        <li><i>度蜜月</i></li>
        <li><a href="http://ww.hana.com”id=" rel="external nofollow" feng">凤凰台上凤凰游，凤去台空江自流，吴宫花草埋幽径，晋代衣冠成古丘</a></li>
    </ul>
</div>

     soup.select( '.tang > ul > li > a') 
     soup.select( '.tang >ul a')
     结果为：[<a href="http://www.baidu.com" title= "ging">清明时节雨纷纷,路上行人欲断魂,借问酒家何处有,牧童遥指杏花村</a>,
     <a href="http://www.163.com" title="qin">秦时明月汉时关，万里长征人未还,但使龙城飞将在，不教胡马度阴山</a>,
     <a href=" http://ww.126.com"alt="qi ">歧王宅里寻常见，崔九堂前几度闻，正是江南好风景,落花时节又逢君</a>,
     <a href="http: //www.sina.com" class="du">杜甫</a>,
     <a href="http://www.dudu.com" class="du">杜牧</a>,
    <a href="http://ww.hana.com”id="feng">凤凰台上凤凰游，凤去台空江自流，吴宫花草埋幽径，晋代衣冠成古丘</a>]

print(soup.select( '.tang > ul > li > a') [0]['href'])
结果：
www.baidu.com