Finding all Examples that have duplicate values in certain attributes

This process will retrieve all examples, who have identical values in a specific attribute. For testing, the following data can be writen into the file, that will be read by the Read CSV operator:

CID,Value 3596,X 4054,X 4054,X 3000,S 3000,T 3000,U 32135,S

The target of this process is to return the two examples having the same value in the CID column.

To achieve this, first a real id is generated by the generate id. After this, we have to find all duplicates: For this we first remove duplicates based on the single attribute CID. We subtract the result from the original example set in order to get all values of CID, that occure more than once. Since they might occur more than once in this set, we use a Remove Duplicates to have each value just once, so that we can join them after defining them to be the id.