Combine rows with same ID / Split column transformation backward

I can not share sample data because i get an error. 

I have one table with dublicated rows. Dublicated becuase one id have different categories. And the goal is to combine the dublicated rows in one with the format you see in my first post. I hope this is understandable.

The challenge is like this:

https://stackoverflow.com/questions/61238999/how-to-combine-rows-with-the-same-id-into-a-list

I want to combine this two columns like this:

ID, Category

1, Green | Blue

It looks like the hint in this link works. I had a mistype in my codings earlier.
This is the solution. Anyway, thank you for your help.