Used for: calculating how many elements a list has.
Used in: "THEN"-statements and "ELSE"-statements.
The "calculate list length" rule calculates of how many elements a list is made up. This could be useful when you have all the available sizes of a product in a list, and you want to calculate how many sizes of a product are available. The rule for this example would look like the screenshot below:
In the screenshot below you can see how this rule would work for a specific product: