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clojurespecter

Removing nested values with Specter in Clojure

Suppose that I have a Clojure map like this:

(def mymap {:a [1 2 3] :b {:c [] :d [1 2 3]}})

I would like a function remove-empties that produces a new map in which entries from (:b mymap) that have an empty sequence as a value are removed. So (remove-empties mymap) would give the value:

{:a [1 2 3] :b {:d [1 2 3]}}

Is there a way to write a function to do this using Specter?

Solution 
  • (update my-map :b (fn [b]
                    (apply dissoc b 
                           (map key (filter (comp empty? val) b)))))