Wednesday, 13 August 2014

How does Web Scraping Identify the Data you Want

The Web is one of the biggest sources of data that should be leveraged for your business. Be it an email, an URL or even a hyperlink text you are looking at, it comprises data that could be translated into useful information for your business. The challenge however lies in identifying the data that is relevant for your needs and enabling access to the required data. Web Scraping tools, however, are geared to help you address this need and leverage the benefit of this huge information repository.

Web Scraping and how it Works?
Web Scraping is the practice followed to extract data from relevant sources on the Web and transforming them into crucial information packages for use in your business. This is an automated process which is executed with the help of a host of intuitive Web Extraction tools, thus facilitating ease, accuracy and convenience in extracting vital data.

Scrapers also work by writing intelligent pieces of code that scour the web and extract data that you need for the benefit of your business. The languages used for coding these scrapers are Python, Ruby and PHP. The language you use will be determined by the community you have access to.

As mentioned earlier, the biggest challenge that web scraping is subjected to include the identification of the right URL, page and element in order to scrape out the required information. No matter how good you may be at coding scripts, no amount of that will help you achieve your objective if you fail to develop an understanding of the way the web is structured. It is this which will enable you to structure your code in a manner that will be the most effective in scraping the desired information.

Understanding a Web Site
A Web Site appears on your browser owing to two technologies. These include:
  • HTTP – The language used to communicate with the server for requesting the retrieval of resources, namely, images, videos, and documents and so on.
  • HTML – The language that helps to display the retrieved information on the browser.

The display format of your website is therefore defined using the HTML. It is within the folds of its syntax, that you will find the data which you need to extract. It is, therefore, important that you understand the anatomy of a web site by studying the structure of an HTML Page.

The HTML Page Structure
An HTML page comprises a stack of elements known as tags, each bearing a specific significance. The first among these being the header tags that comprises mostly all the elements within it. The table element, the most important so far as data containers are concerned, is a crucial element that you need to study. It comprises several table rows (TR) and table data (TD) elements that hold the vital data nuggets that you might need to train your scrapers to extract.

In addition to these, HTML pages comprise a series of other tags that act as vital data holders, namely, image tags (img src), hyperlinks (a href) and the div tags which essentially refer to a block of text.
The scraper code needs to be built around your understanding of the HTML elements. Knowing the elements will help you to understand the specific location where relevant data are stacked. This helps you to correctly define the code so as to enable the scraper to search and extract the right element in order to provide you with the most appropriate information.

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