Hello, I trying to achieve something similar to @mix in the following post https://forum.dynamobim.com/t/lacing-on-replacing-item-on-index/16462
However I’m looking to just reduce a list by 12 elements. In my case it’s 12 sheets but for the exercise it really doesn’t matter what the list is, the other difference is that I’m looking at text parameters to be able to select the difference between the two lists (boxed in red), and then remove the elements from the master element list (boxed green), rather than the text list. So I’m looking at the sheet numbers as a filter to differentiate between the two list, the order is important as well, as I don’t want to remove the wrong sheet. I also tried the code put forward by @Nick_Boyts but I must have done something wrong because it did work for me. In the past I have used a Boolean filter to be able to reduce a master list, but it doesn’t seem applicable here, although I have used it to illustrate the step by step process. Any help or thoughts will be appreciated.