Comparing Lists and Removing Values

[Rich_E]

How would I create a valid_if formula to compare 2 lists and then remove values that exist or do not exist in another list?

For example, I have List A and List B. I want to use a valid_if to only allow entries that “do not” exist in List B but exist in List A.

[tony1 · Accepted solution]

You could try this: [List A] - [List B]

See “List Subtraction” here: https://help.appsheet.com/expressions/expression-types/list-expressions-and-aggregates