Meta-Node running through columns


I’m looking to develop a Meta-Node that would permit to run through each columns of my data. It would help me execute a sub-java node that would be executed on each column. My goal is to discretize data on a huge range of columns.
But when I tried to develop this meta-node, I came across a lot of problems. The only solution I was able to think of was to isolate the current column, and leave it alone in the data. At the end of the meta-node, replicate the modification on the actual datas. But I didn’t do it as it was not clean.
As I developed, I also came across the Flow-Variables concept, but I’m still not sure I understand it well. I can’t find any documentation on this topic. But it looks like it permits to change a parameter of a node by a variable?
So here are my questions, is there by any chance an existing meta-node doing what I’m trying to do?
And, may I find a solution using Flow-Variables?

Thank you in advance for your answers.

In fact I recently had the same problem and wrote a loop start node. If your are using the developer version I can send you the source code and you may give it a try (at your own risk, of course ;-)).

Yes, I’m very interested by your source code. I have developed my own Discretization node, but it’s doing a very specific task.
I think a Loop running through columns might be very useful when nodes doesn’t propose any option to select multi-columns.