from lxml import etree

  2 text = '''

  3 <div>

  4 <ul>

  5 <li class = "item-0"><a herf = "link1.html">first item</a></li>

  6 <li class = "item-1"><a herf = "link2.html">second item</a></li>

  7 <li class = "item-inactive"><a herf = "link3.html">third item</a></li>

  8 <li class = "item-1"><a herf = "link4.html">fourth item</a></li>

  9 <li class = "item-0"><a herf = "link5.html">fifth item</a></li>

 10 </ul>

 11 </div>

 12 '''

 13 html = etree.HTML(text)

 14 result = etree.tostring((html))#输出修正后的HTML文本

 15 code_all = html.xpath("//*")#选取HTML全部的节点

 16 code_li = html.xpath("//li")

 17 code_a = html.xpath("//li/a")#选取HTML的li节点的子节点a

 18 code_p = html.xpath("//a[@herf = 'link4.html']/../@class")#一直子节点寻找父节点的class属性

 19 print(code_p)

 20 print(code_li)

 21 print("///")

 22 print(code_all)

 23 print("///")

 24 print(code_a)

 25 #属性匹配

 26 attribute = html.xpath("//li[@class = 'item-0']")

 27 print(attribute)

 28 #文本获取

29 text = html.xpath("//li/text()")

 30 print(text)

 31 #属性获取

 32 attribute_get = html.xpath("//li/a/@herf")

 33 print(attribute_get)

 34 #属性多值匹配

 35 text1 = """

 36 <li class = "li li-fist"><a href = "link.html">first item</a></li>

 37 """

 38 html1 = etree.HTML(text1)

 39 attribute_number = html1.xpath("//li[contains(@class,'li')]/a/text()")

 40 print(attribute_number)

 41 #多属性匹配

 42 text2 = """

 43 <li calss = "li li-first" name = "name"><a href = "link.html">first item</a></li>

 44 """

 45 html2 = etree.HTML(text2)

 46 attribute_text2 = html2.xpath("//li[contains(@calss,'li') and @name = 'name']/a/text()")

 47 print(attribute_text2)

 48 #按序选择

 49 """

 50 有时候，我们在选择的时候某些属性可能同时匹配了多个节点，但是只想要其中某个节点

 51 这是可以利用中括号传入索引的方法获取特定次序的节点

 52 """

 53 text3 = '''

 54 <div>

 55 <ul>

  <li class = "item-0"><a herf = "link1.html">first item</a></li>

 57 <li class = "item-1"><a herf = "link2.html">second item</a></li>

 58 <li class = "item-inactive"><a herf = "link3.html">third item</a></li>

 59 <li class = "item-1"><a herf = "link4.html">fourth item</a></li>

 60 <li class = "item-0"><a herf = "link5.html">fifth item</a></li>

 61 </ul>

 62 </div>

 63 '''

 64 html3 = etree.HTML(text3)

 65 result = html3.xpath("//li[1]/a/text()")#选取第一个li节点

 66 print(result)

 67 result = html3.xpath("//li[last()]/a/text()")#选取左后一个li节点

 68 print(result)

 69 result = html3.xpath("//li[position() < 3]/a/text()")#选取位置小于三的节点

 70 print(result)

 71 #节点轴选取

 72 result = html3.xpath("//li[1]/ancestor::*")#获取所有祖先节点，后跟*表示匹配所有节点

 73 print(result)

 74 result = html3.xpath("//li[1]/ancestor::div")#获取div这个祖先节点

 75 print(result)

 76 result = html3.xpath("//li[1]/attribute::*")#获取所有属性

 77 print(result)

 #运行结果

    ['item-1']

[<Element li at 0x7f72f489c888>, <Element li at 0x7f72f489c948>, <Element li at 0x7f72f489c9c8>, <Element li at 0x7f72f489ca08>, <Element li at 0x7f72f489ca88>]

///

[<Element html at 0x7f72f489c808>, <Element body at 0x7f72f489c788>, <Element div at 0x7f72f489c748>, <Element ul at 0x7f72f489c848>, <Element li at 0x7f72f489c888>, <Element a at 0x7f72f489c908>, <Element li at 0x7f72f489c948>, <Element a at 0x7f72f489c988>, <Element li at 0x7f72f489c9c8>, <Element a at 0x7f72f489c8c8>, <Element li at 0x7f72f489ca08>, <Element a at 0x7f72f489ca48>, <Element li at 0x7f72f489ca88>, <Element a at 0x7f72f489cac8>]

///

[<Element a at 0x7f72f489c908>, <Element a at 0x7f72f489c988>, <Element a at 0x7f72f489c8c8>, <Element a at 0x7f72f489ca48>, <Element a at 0x7f72f489cac8>]

[<Element li at 0x7f72f489c888>, <Element li at 0x7f72f489ca88>]

[]

['link1.html', 'link2.html', 'link3.html', 'link4.html', 'link5.html']

['first item']

['first item']

['first item']

['fifth item']

['first item', 'second item']

[<Element html at 0x7f72f489cdc8>, <Element body at 0x7f72f489cec8>, <Element div at 0x7f72f489cf48>, <Element ul at 0x7f72f489cf08>]

[<Element div at 0x7f72f489cf48>]

['item-0']