1. 测试HTML代码
# 测试代码test.html
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<div class='main-content'>
<h1 id="title">This is a test!</h1>
<p class="main-content ref">This is paragraph1</p>
<div>
<p>测试语句1</p>
</div>
</div>
<div>
<p>This is paragraph2</p>
<div>
<p class="ref">测试语句2</p>
</div>
</div>
</body>
</html>
2. etree.HTML( )
调用HTML类对HTML文本进行初始化，成功构造XPath解析对象，同时可以自动修正HMTL文本（标签缺少闭合自动添加上）
from lxml import etree #首先导入lxml库的etree模块
with open('test.html','r') as f:
c = f.read()
#调用HTML类进行初始化，成功构造XPath解析对象
tree = etree.HTML(c)
3. etree.tostring()
tostring( )方法可以输出修正之后的HTML代码，也可以直接读取文本进行解析，但是结果为bytes类型，因此需要利用decode()方法将其转成str类型
具体的decode( )格式需要浏览器审查页查看
import requests
from lxml import etree
with open('real_case.html', 'r', encoding='utf-8') as f:
c = f.read()
tree = etree.HTML(c)
table_element = tree.xpath("//div[@class='table-box'][1]/table/tbody/tr")
for row in table_element:
try:
td1 = row.xpath('td')[0]
#具体的转成什么格式，需要审查网页元素，查看
s1 = etree.tostring(td1).decode('utf-8')
print(s1)
except Exception as error:
pass
