Table difference (iterating)

KNIME Analytics Platform
1

Hello,

So I need to build a movie recommendation system for this uni project. What I'm stuck in right now is to get the difference between two tables, BUT:

Table 1 has:

User ID - Movies ID - Rating

Table 2 has:

Movie ID - Category Bitvector

 

What I need to do is to get the Movie ID each user hasn't rated/watched yet. So I need a table with, for each user, the difference between table 2 and 1, that are the movies that aren't listed in table 1.

I've tried using Reference row filter for only 1 user, and tried iterating with Group loop, but it only gives me the first group of users which is User ID 1. So I'm stuck in here.

Here is a picture of my current state:

http://imgur.com/ssEKPkO

 

Any help is appreciated, and thanks in advance!

2

Hello mhnjqm,

imgur is over capacity, but I created a simple workflow that does what you need:
You have your list of movies and the list of ratings as inputs. Then you Group-Loop over the UserID. In the loop, you use the reference row filter to exclude the movies from the movie-list which are present in the output of the group loop start. Then you use a constant value column to append the userID (which you get automatically as a flow variable) and close it with a loop end. Done.

Best,
Ferry