There are actually 5 loop modes in Octoparse: Variable List, Single Element, Fixed List, List of URLs, and Text List.
Variable List is the most frequently used loop mode in Octoparse. It is widely used to locate items in similar layout, especially when dealing with dynamic websites because Variable List Mode will automatically detect and match all the items corresponding to a certain XPath. For example, there will be more tweets in the same twitter page if you keep scrolling down to the bottom of the screen. So you need to keep adding new tweets shown in the page to the loop list. That is what Variable List Mode can do for you! Every time there are new tweets shown, Octoparse will automatically add them to the list right away.
Single Element is to locate just one single item matched with a XPath, especially to normal pagination by loop clicking a button. Click here to see an example.
Fixed List is opposite to Variable List as it can not automatically add new items but just add items according to the fixed list of XPath you enter to the box. The items added to the list will not change even in dynamic pages. Check the example here.
List of URLs is to make a list of URLs for Octoparse to browse one by one. It can be used when you have many pages with similar format like Amazon product detail pages. Click here to see an example.
Text List Mode is used when you need to enter different text values for example entering different keywords in searching box. Click here to see an example.
Fixed List, List of URLs, and Text List are all used to make a list with certain number of items. These three modes are often used in Cloud Extraction to speed up the extraction process. Every item in the list will be assigned to a cloud server to shorten the extraction time.