How do I check for duplicates within a map in clojure?

Question

So I have a list like the following:

({:name "yellowtail", :quantity 2} {:name "tuna", :quantity 1} 
{:name "albacore", :quantity 1} {:quantity 1, :name "tuna"})

My goal is to search the list of map items and find duplicates keys, if there are duplicates then increment the quantity. So in the list I have two tuna mapped elements that show up. I want to remove one and just increment the quantity of the other. So the result should be:

({:name "yellowtail", :quantity 2} {:name "tuna", :quantity 2} 
{:name "albacore", :quantity 1} )

With :quantity of tuna incremented to 2. I have attempted to use recur to do this without success, I'm not sure if recur is a good direction to run with. Could someone point me in the right direction?

Answer 1

You can group-by :name your elements and then map through the grouped collection summing the values.

Something like this

(->> your-list 
  (group-by :name) 
  (map (fn [[k v]] 
         {:name k :quantity (apply + (map :quantity v))})))   

P.S. I assume you need to sum quantity of elements, because it's not clear what exactly you need to increment.