提交代码

Author: cxhuan

xianhuan/README.md

@@ -10,6 +10,8 @@ Python技术 公众号文章代码库
 
 ## 实例代码
 
+[肝了三天三夜，一文道尽Python的xpath解析！](https://github.com/JustDoPython/python-examples/tree/master/xianhuan/xpath)：肝了三天三夜，一文道尽Python的xpath解析！
+
 [丢弃Tkinter，这款GUI神器值得拥有！](https://github.com/JustDoPython/python-examples/tree/master/xianhuan/gooey)：丢弃Tkinter，这款GUI神器值得拥有！
 
 [知乎热门：如何提高爬虫速度？](https://github.com/JustDoPython/python-examples/tree/master/xianhuan/spiderspeed)：知乎热门：如何提高爬虫速度？

xianhuan/xpath/xpathstudy.py

@@ -0,0 +1,96 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+@author: 闲欢
+"""
+from lxml import etree
+
+text = '''
+<div>
+            <ul id='ultest'>
+                 <li class="item-0"><a href="link1.html">first item</a></li>
+                 <li class="item-1"><a href="link2.html">second item</a></li>
+                 <li class="item-inactive"><a href="link3.html">third item</a></li>
+                 <li class="item-1"><a href="link4.html"><span>fourth item</span></a></li>
+                 <li class="item-0"><a href="link5.html">fifth item</a> # 注意，此处缺少一个 </li> 闭合标签
+             </ul>
+         </div>
+'''
+
+# 调用HTML类进行初始化，这样就成功构造了一个XPath解析对象。
+page = etree.HTML(text)
+print(type(page))
+print(etree.tostring(page))
+
+# nodename
+print(page.xpath("ul"))
+
+# /
+print(page.xpath("/html"))
+
+# //
+print(page.xpath("//li"))
+
+# .
+ul = page.xpath("//ul")
+print(ul)
+print(ul[0].xpath("."))
+print(ul[0].xpath("./li"))
+
+# ..
+print(ul[0].xpath(".."))
+
+# @
+print(ul[0].xpath("@id"))
+
+# 谓语
+# 第三个li标签
+print(page.xpath('//ul/li[3]'))
+# 最后一个li标签
+print(page.xpath('//ul/li[last()]'))
+# 倒数第二个li标签
+print(page.xpath('//ul/li[last()-1]'))
+# 序号小于3的li标签
+print(page.xpath('//ul/li[position()<3]'))
+# 有class属性的li标签
+print(page.xpath('//li[@class]'))
+# class属性为item-inactive的li标签
+print(page.xpath("//li[@class='item-inactive']"))
+
+
+# 获取文本
+# text()
+print(page.xpath('//ul/li/a/text()'))
+# string()
+print(page.xpath('string(//ul)'))
+
+# 通配符
+print(page.xpath('//li/*'))
+print(page.xpath('//li/@*'))
+
+# |
+print(page.xpath("//li|//a"))
+
+# 函数
+# contains
+print(page.xpath("//*[contains(@class, 'item-inactive')]"))
+
+# starts-with
+print(page.xpath("//*[starts-with(@class, 'item-inactive')]"))
+
+
+# 节点轴
+# ancestor轴
+print(page.xpath('//li[1]/ancestor::*'))
+# attribute轴
+print(page.xpath('//li[1]/attribute::*'))
+# child轴
+print(page.xpath('//li[1]/child::a[@href="link1.html"]'))
+# descendant轴
+print(page.xpath('//li[4]/descendant::span'))
+# following轴
+print(page.xpath('//li[4]/following::*[2]'))
+# following-sibling轴
+print(page.xpath('//li[4]/following-sibling::*'))
+
+