Merging example

I'd break this down step by step.

First, the keys of each map seem to be irrelevant, so we can get rid of them by `map`ping `vals` over your data (which I'll call `data`):

    (map vals data)
    
    (([{:ms "A", :s 1, :v 15}] [{:ms "A", :s 2, :v 18}] [{:ms "A", :s 4, :v 19}])
     ([{:ms "A", :s 1, :v2 5}] [{:ms "A", :s 2, :v2 8}] [{:ms "B", :s 4, :v2 9}]))

But that leaves some ugly nested lists. I removed them by using a 2D `map`:

    (map #(map first %) data2) ; Could have also used partial
    ; Over each outer list, get the first element of each inner list
    
    (({:ms "A", :s 1, :v 15} {:ms "A", :s 2, :v 18} {:ms "A", :s 4, :v 19})
     ({:ms "A", :s 1, :v2 5} {:ms "A", :s 2, :v2 8} {:ms "B", :s 4, :v2 9}))

The data looks much more manageable now. Lastly, I think we just need to `merge` each of the two lists of maps together:

    (apply map merge data3))
    ; Apply each sublist to merge. This would be the same as deconstructing out each sublist, then writing (map merge sublist1 sublist2)

    ({:ms "A", :s 1, :v 15, :v2 5} {:ms "A", :s 2, :v 18, :v2 8} {:ms "B", :s 4, :v 19, :v2 9})