I'm looking to implement something like a 'for loop' in RapidMiner. The input to the 'for loop' will be a dataset of say 5 attributes. For each run of the 'for loop', I need to add one new attribute. So if the 'for loop' runs 5 times, I end up with a dataset of 10 attributes. With the Loop operator the dataset that goes into the loop is the initial one with 5 attributes. How do I append attributes for each run and get that new dataset with the additional attribute as the input for the next run of my Loop operator? Or should I be using some other operator for this?