In a case where I have vector of maps, each of those vectors houses another vector of maps. How should I collect and operate the sub vector and it's maps. so that Maps on the first level are transformed, and the submaps are transformed? My current code ( in thread ) doesn't work. as when I try to output it, the expression merges all the subvector's maps into a single vector and does, preventing repeat of the parent map. I'm feeling I should be able to do a partition based on the parent map somehow but I cannot get the expression right.

Never-mind. the answer is ..!n instead of ... I'm sorry to have bothered over nothing. It seems to retain the parent relationship.