In this article, you will learn about the advantages and differences between web crawling and web scraping. Learn how these methods are used to extract data from websites and gain insight into their applications.
Data is not always written in a form that is convenient to process. A simple example is a complex and unreadable website address on a manager's paper business card. It turns out that in order for the client to access this data (to convert it from a drawn form into a symbolic input inside the browser's address bar), letters, numbers and other symbols must be manually typed on the keyboard.
But the format can be changed by putting a QR code on the business card or using an NFC tag. Then the necessary information can be easily read using special programs like email scraping tools. And the user will not make a mistake, and the input process will be noticeably faster.
But the format can be changed by putting a QR code on the business card or using an NFC tag. Then the necessary information can be easily read using special programs. And the user will not make a mistake, and the input process will be noticeably faster.
Approximately the same situation occurs when the data being searched for, stored on the computer's hard drive, is actually in an "unreadable" form, that is, incompatible with programs. After all, each program is designed to read only those formats that its developers have provided. And if the existing formats are not supported, then the program will not be able to read the file.
Now another example: imagine that you need to collect a database of email addresses, but they are stored inside PDF files, images (photographs of business cards), an email client, in business documents, etc. How can you collect the necessary information in one place and at the same time convert it into a more convenient (readable) format?
A parser program (scraper) will help. It can open files of different types, find the necessary information in them and save the data in another format (usually in the form of tables or lists, but there may be other formats, such as XLM markup, etc.).
The process of searching for information and converting it into a new type/format is called parsing or scraping.
Previously we talked about what parsing is.
From the English word scraping - "scraping" or "scraping". As a result, we get the following definition.
Scraping is the process of searching and converting data into a more convenient format suitable for analysis, storage, indexing, etc.
Web scraping, as can be understood from the prefix "web", is the search and conversion into a convenient format of web data. That is, information posted on the pages of sites and services on the Internet.
Web scrapers are the most widespread. Why?
Web scrapers can operate as standalone software on the user's equipment (on his PC or on a virtual/dedicated server), or deployed in the cloud (provided as a service, SaaS or PaaS format). In some cases, scrapers can be part of more complex software packages as one of the system elements.
The tasks and goals of web scrapers can be anything from positive, aimed at creation and improvement, to negative, aimed at industrial espionage, detection of security holes, etc.
The most popular tasks for business:
If the advantages of parsers/scrapers are more or less clear (they help in solving applied problems), then few people talk about the disadvantages. Let's correct this injustice.