Understanding The Basics of Data Mining3892015

Web scraping (data extraction), as the name suggests, is a technique of extracting information from websites. While there are a number of methods involved in this practice, some basic principles help ensure good results at scraping. Here’s a list of those practices I have always found useful and hope they will work for you as well.

Split your Data into Pieces

We normally deem web unreliable where even a very dependable connection can be lost at any time. For this reason, it is a good practice to break all data into separate pieces so that each piece may be loaded separately. Thus, if the connection or data gets overloaded and you are unable to receive any data, the remaining sections are not affected and you can save them for further processing at a later stage. This idea is especially helpful when you have to load a large amount of data, leaving your computer to work for hours and days. It makes Web scraping (data extraction) a lot convenient.

Parse and Save

When you scrape a new site, the best thing to do is to take all the data and save it to disk rather than trying to process it as soon as it comes from the server. This will save you time and will likely prevent you from being banned.

For instance, if you need to scrape some 100 pages, parse and save it to your database. If you do otherwise, you may come across a structure difference on the 90th that breaks your scraping algorithm. You will need to adjust it and begin from square one, which means a lot of wasted time.

Check Statistics

When you scrape MBs and GBs of information, statistics are helpful. It is suggested that you setup some metrics and evaluate the quality of the output through them. For instance, if you are scraping user information, you can check the number of male and female visitors. If the ratio appears incorrect, check your algorithm for possible errors. This ensures smooth web scraping operation.

Detailed info on web harvesting can be found on the main website.