Semalt: The HTML Scraping Guide – Top Tips

Web content is mostly in structured or HTML formats. Every page is organized in its unique way depending on the kind of content in it. If someone wants to extract web information, it is each person's wish to obtain the data in a structured and well-organized manner. This will help in saving the time required for reviewing, analyzing and organizing the document before sharing it. However, getting the structured format is not easy since most websites do not offer that option to prevent people from extracting large amounts of data. Some sites, however, provide the APIs which provides people with information extraction option in a quick and easy process.

In such events, you will have no choice but to use the help of a software programming known as scraping. It is an approach that uses computer program helping users to gather information in a useful format and preserving the data's structure.

Lxml and Request

This is a wide-ranging scraping library that helps in analyzing and evaluating XML and HTML fast and helps in saving time. It is also helpful in dealing with messed up tags in the analyzing process. In this procedure, you use Lxml requests rather than the inbuilt urllib2 since it is faster, robust and readily available. It is easy to install it by using pip install Lxml and pip install requests.

For HTML scraping follow these steps

Start by imports - here you import HTML from Lxml, then import request. Use request and then trace the web page containing the data that you wish to extract, analyze it by HTML module and then save the parsed data in the tree.

You will need to use the page content rather than text since HTML expects to receive the input in bytes. The tree, where you stored your analyzed data now contains the HTML document in a tree structure. You can go over the tree structure in different approaches, the XPath and CSSelect.

XPath helps you to retrieve information or obtain it in a structured format like HTML or XML. There are various ways in which you can get the XPath elements. These include Firebug for Firefox or Chrome Inspector. When using Chrome, inspecting information is easy since you only need to 'right' click the element that requires inspection, select 'Inspect element,' highlight the code provided and then right click and select copy XPath. This process will help you know which elements are contained in your page and from there, it is easy to create the right XPath query and apply the Lxml XPath correctly.

Going through these steps ensures that you have scraped all the data you wanted to extract from a particular web using Lxml and Requests. You will have the information stored in a two list memory, and now it is ready for sorting. You can analyze it using a programming language like Python or save it and share it. Also, you may wish to rewrite or edit some parts of the information before sharing it.