Combine/merge lists by elements names (list in list)

Question

I have two lists, whose elements have partially overlapping names, which I need to merge/combine together into a single list, element by element:

My question is rela

Answer 1

This is a kind of a nested merge function which seems to produce the output you desire. I feel like there should be a more simple way but I can't think of one. It will prefer values from the first parameter, but will merge with values from the second parameter if there is a matching name or index.

nestedMerge<-function(a,b) {
    if(is.list(a) & is.list(b)) {
        out<-list()
        if(!is.null(names(a))) {
            for(n in names(a)) {
                if(n %in% names(b) && !is.null(b[[n]])) {
                    out<-append(out, list(Recall(a[[n]], b[[n]])))
                } else {
                    out<-append(out, list(a[[n]]))
                }
                names(out)[length(out)]<-n
            }
        } else {
            for(i in seq_along(a))
                if(i <=length(b) && !is.null(b[[i]])) {
                    out<-append(out, Recall(a[[i]], b[[i]]))
                } else {
                    out<-append(out, list(a[[i]]))
                }
        }
        return(out)
    } else {
        return(list(c(a,b)))
    }
}

#and now, use the function
nestedMerge(l.1,l.2)