A Predicate is a delegate, which basically a delegate is a pointer to a function. Unfortunately though, I would not recommend working with delegates in FlowCanvas because things can become very complicated quickly, since within FlowCanvas, support for assigning a method to a delegate is not supported (at least right now).
For what you are after, I would either recommend the typical for-loop approach, or even the creation of a custom node [LINK] that takes a list, processes it as you desire, and finally returns the processed list as an output.
Gavalakis
