Hi there, think this is a common issue and it has to do with loops. The problem I keep running into is that the set command appears to execute values differently than outside the loop. If I assign some value to an alias, somehow I find its definition inside the loop i.e. Part::pkspec1: The expression Join[If[{}[[1]]=={20,21},5],{}] cannot be used as a part specification.. I'm confused why this should be happening, the documentation does appear to suggest that the assignment is completed at
