Create a formula to concat a look up field with another field?

I’m having a lot of difficult creating a formula field to concat a look up field with another field, to create a new field. The issue is that the lookup field generates an array with a value, and it’s not clear how to get that value in the formula. Here is what we want to do. We have a field called: “name_key” which is a look up field. It can for example, generate a value like this: OPL_STANDARD. We then have a number field called order, which can generate a value, like: 4. The formula field should generate a concatenation of those 2 fields like so: OPL_STANDARD_number_4 - so it’s a concat of name_key + “number” + order (using basic JS syntax). I tried using AI to generate the join and concat, but it throws an error, because the lookup field is not a string, but an array. Any ideas?

Edit: So the look field, returns an array in the formula, something like this: [{id: 1, value: “standard”}] - but how do we get the value back without the array? There doesn’t seem to be any formula functions that parse the array from the lookup field to get the value?

Hi @ddsgad, I’ve tried to recreate your scenario. Is this the result you’re looking for?