We have a flow that loops through 2 objects (User & Email message) and stores its email addresses in 2 collections (Co11 and col2). I want to compare 2 collections and get unique elements before i send out an email to unique email addresses. I tried to loop through and use a decision outcome to see if the col1 contains in col2 however there seems to be a limitation on CONTAINS function. I looked up This question but doesn't seem to find any solution. Is there any way we can compare 2 collections from flow and get unique elements without writing APEX? If not, how do i compare 2 input collections in apex and pass it back to flow from apex? Thank you!
As per the documentation, CONTAINS only compares strings so cannot be used to compare collections.
Take a look at (and perhaps vote for) this idea and note the references to unofficialsf.com where you will find pre-build List actions for Flows that you can incorporate into your solution instead of writing the code yourself.