Calculating sum/difference of two lists including empty lists

[bvs1982]

I am not sure if i understand the question correctly but maybe you can replace an Empty List for 0.

Replace empty list with list (eg. replace empty list with [A,B,C] )

@Macchi I don’t think that worked as you expected. Look at the values of your sublists. They’re just being repeated. Here’s a simple python code that will do the trick: output = [] for a in IN[0]: if len(a) == 0: output.append(IN[1]) else: output.append(a) OUT = output [image]

NB
Post (an image of) your whole graph or the .dyn so people can help you better.