lxml解析
from lxml import etree
text='''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1"><!-- Elsie --></a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
'''
html=etree.HTML(text)
#读取文件
#html=etree.parse('test.html')
result=etree.tostring(html)
print(result)
输出结果，补全了html的标签
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1"><!-- Elsie --></a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
</body></html>
获取a标签和a的class
print html.xpath('//a')
#[<Element a at 0x10bdc0cb0>, <Element a at 0x10bdc0c68>, <Element a at 0x10bdc0b90>]
print html.xpath('//a/@href')
#['http://example.com/elsie', 'http://example.com/lacie', 'http://example.com/tillie']
