Clojure: summing values in a collection of maps

Question

I am trying to sum up values of a collection of maps by their common keys. I have this snippet:

(def data [{:a 1 :b 2 :c 3} {:a 1 :b 2 :c 3}]
(for [xs data]          


        

Answer 1

If you really want to sum the values of the common keys you can do the whole transformation in one step:

(apply merge-with + data)
=> {:a 2, :b 4, :c 6}

To sum the sub sequences you have:

(apply map + '((1 2) (1 2)))
=> (2 4)