Note: NOT a native feature in Glide.
Tutorial coming tomorrow—here’s a (soundless) sneak peak! For context, there’s one master list of items. I’m switching between two users that are linked via a “lead” email. The adding/removing of items from this master list is unique to these two users. Other users in the app have their own set of tools!
Interesting! Will def check out the tutorial!
I wonder what other use cases this “Trebuchet Method” could be used for…
So I have a question. Maybe I missed something, but couldn’t you skip the temporary column altogether. So your template column would always contain the existing list of selected items already joined to the item in that row. When the action is executed, it slings the template over to the user sheet and automatically pulls in the updated list of selected items to your list sheet. Maybe I’m wrong, but the template column seems like an extra step.
The template column combines the existing list with the new item.
Right, but couldn’t you shortcut a step and join the row id directly to the existing list, instead of first writing to a temporary column?
Oh…TEMPORARY column…I read it as template column…perhaps…
Yes, for sure it works with the ADD item to list (just tested). 99% sure (now) that you still need it for the remove item functionality.
Hooray for skipping steps!
Yep, I can see where it’s needed for the removal. Just trying to simplify. 
I might need to watch the video a couple more times. Nice work!
Using this functionality, you can probably do a bulk award to user (if using relations/lookups to calculate balances). Hopefully one day we can do set columns and delete rows via multiple relation (@mark 
). Then the Trebuchet method would take Glide apps to the next level!
Here’s my video explaining how and why I create this method I’ve posted 3 weeks ago.
It is in Portuguese, but you can use YouTube translation
Who’s curious to know more about it, can watch here:
heh, I smiled when I saw what you did with the if-then-else to handle the first item in the list. I had exactly the same challenge in my Global Announcement tracking demo. I solved it in a similar (but not identical) way:
One thing I hadn’t figured out was a good way to remove items (users) from the list, so was particularly interested in what you did there. Very clever and will definitely be making use of that. Thanks!
Yes! I first used this method back in early December to develop my group chat template, but like you, I didn’t have a good way of removing users from a list. Then, in mid-January, @Lucas_Pires found out how to remove users using a user specific column followed by a join list. He dubbed this complete method the Trebuchet and the rest, as they say, is history!
But I created the method and improved the way we remove a user/item from a list too.
The difference was I didn’t have time to post here. And now I’m back.
Funnily I didn’t know this was known as the trebuchet method. My zigzag pattern based on same logic. Interesting 
Me neither! I think once the set column action came out, many of us tried to do something like this. I used the first half of this method back in Nov/Dec but couldn’t figure out how to remove items from an array. It wasn’t until I met with @Lucas_Pires did I learn that you don’t remove items from the existing array, but rather create a new array and overwrite. He’s the one who branded it the Trebuchet method. I thought it was catchy and branded it as such. But whatever you call it…zigzag, boomerang, trebuchet, array-column-overwriting…it’s an awesome method.
I actually like the name trebuchet- sounds glidEinstein 
Another good name 
!
