Normalize IDs column
I would go through and find the item with the smallest id in the list, set it to 1, then find the next smallest, set it to 2, and so on.
edit: you are right. That would take way too long. I would just go through and set one of them to 1, the next one to 2, and so on. It doesn't matter what order the ids are in (I am guessing). When a new item is added just set it to 9067, and so on.
I'm making a recommender system, and I'd like to have a matrix of ratings (User/Item). My problem is there are only 9066 unique items in the dataset, but their IDs range from 1 to 165201. So I need a way to map the IDs to be in the range of 1 to 9066, instead of 1 to 165201. How do I do that?