Turn from: http://www.cnblogs.com/qingchunjun/p/4208159.html
By.xpath ()
This method is a very powerful way to find elements, which can be used to locate almost any element on the page. Before we can formally start using XPath for positioning,
In selenium automation, if the ID, class, name, etc General Locator cannot find the element, the XPath is used to find the element on the Web page.This time I will explain from the following three aspects:1. What is XPath2. Use of XPath syntax3. Use
Tell you, you always rely on that firebug,chrome F12 what right click Copy XPath absolutely one day on the mine bombing you are not able to locate, this time you need to learn to write XPath, the human brain is smarter than the computer, and began
in the Web page crawl, the analysis of the location of the HTML node is the key to capture information, I am using the lxml module (to analyze the structure of the XML document, of course, can also analyze the HTML structure), Use its lxml.html
Start crawlerIn the previous section, we have created our Scrapy project, looking at this pile of papers, presumably a lot of people will be a face, how should we start this crawler?Now that we've created the Scrapy crawler with the cmd command,
SLT 2.0 with XPath 2.0. They are described separately because XPath 2.0 can also be used in environments other than XSLT, such as XQuery 1.0. But for XSLT users, they are interrelated. You cannot use XPath 2.0 in XSLT 1.0, or use XPath 1.0 in XSLT 2.
We have too many choices in terms of crawling and parsing content.For example, many people feel that jsoup can solve all problems.Both HTTP requests, DOM manipulation, CSS query selector filtering are very handy. The key is this selector, only one
recently learned to use the Scrapy framework to write a reptile, simple crawler is to crawl from the Web page, parse the page, and then data storage and analysis, from the Web page parsing to the data conversion storage. The analytical techniques
The furthest distance in the world is probably to see a page element chu there, but I can't locate it!!
There are many ways to locate elements, such as through IDs, name, Class_name, Tag_name, Link_text, and so on, but the limitations of these
1. XPath (XML Path Language) XML Pathname language2. XPath Common rules:NodeName Select all child nodes of this node/Select a direct child node from the current node.Select descendant nodes from the current node. Select the current node... Select
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