Hi guys 🙂 I’m doing advent of code challenges with clojure (learning it right now) and got stuck on something really stupid. I’ve got the following code for the 5th day parsing the first part of the input (with the containers). The result from the last map is seq of those maps. {:curr-el 10, :4 [], :7 [\V], :1 [], :8 [], :9 [\L], :2 [], :5 [\M], :3 [], :6 []} {:curr-el 10, :4 [], :7 [\G], :1 [\G], :8 [], :9 [\D], :2 [], :5 [\V], :3 [], :6 [\C]} {:curr-el 10, :4 [], :7 [\Z], :1 [\J], :8 [\C], :9 [\J], :2 [], :5 [\Q], :3 [], :6 [\W]} {:curr-el 10, :4 [\W], :7 [\D], :1 [\W], :8 [\G], :9 [\C], :2 [], :5 [\G], :3 [], :6 [\V]} {:curr-el 10, :4 [\N], :7 [\C], :1 [\R], :8 [\M], :9 [\W], :2 [], :5 [\B], :3 [\G], :6 [\D]} {:curr-el 10, :4 [\C], :7 [\N], :1 [\F], :8 [\N], :9 [\N], :2 [\M], :5 [\S], :3 [\H], :6 [\T]} {:curr-el 10, :4 [\R], :7 [\B], :1 [\T], :8 [\J], :9 [\P], :2 [\W], :5 [\F], :3 [\N], :6 [\R]} {:curr-el 10, :4 [\J], :7 [\H], :1 [\Z], :8 [\S], :9 [\G], :2 [\G], :5 [\W], :3 [\J], :6 [\S]} Then I’m trying to merge them into one map, but first remove the curr-el, cause I don;t need it anymore. Unfortunately the acc here is nil and I’m not really sure why. As far as i Know reduce accepts a fn that accepts [accumulator, current-element] The current element is one of those maps, but the acc is nil. Another part of the question is should I do something else in case that I want to append the values of those vectors in the end? Btw I tried merge-with conj/into instead of this reduce but it didin’t worked at all also

(->> (str/split containers #"\n")
       rest
       (map mapper)
       (map (partial reduce create-supply {:1 [] :2 [] :3 [] :4 [] :5 [] :6 [] :7 [] :8 [] :9 [] :curr-el 1})) 
       (reduce (fn [acc el] 
                 (let [removed (apply dissoc el [:curr-el])
                       result (merge (doto removed prn) (doto acc prn))])) 
               {:1 [] :2 [] :3 [] :4 [] :5 [] :6 [] :7 [] :8 [] :9 []}))