Some do not allow you to write your own XPath / CSS / regular expression selectors some only support CSS or XPath but not the other. Many visual scrapers require you to pay for their services beyond a small number of trial extractions, may only store your data for a limited time, and may not provide a way for you to take your scraper off their site for reuse or extension. Visual scraping tools vary in how flexible they are (in comparison to the full expressiveness of coding your own), how easy to use, to what extent they help you identify and debug scraping problems, how easy it is to keep and transfer your scraper to another service, and how costly the service is. They require little or no code, and assist in designing XPath or CSS selectors. Visual scrapers are tools in which the user can visually select the elements to extract, and the logical order to follow in performing a sequence of extractions. Use CSS selectors to refine what needs to be scraped when data is less structured. Practice scraping data that is largely well structured, merging data from many pages. Introduce the Chrome Web Scraper extension.
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