This was my first thought (quite close to Jim's):

(def the-maps [{:key 3 :value 30} {:key 4 :value 40}])

(def mandatory-keys [1 2 3 4 5])

(defn find-missing-keys [maps keys]
  (let [found (into #{} (map :key maps))]
    (remove #(contains? found %) keys)))

(defn ensure-mandatory-keys [maps]
  (let [missing (find-missing-keys maps mandatory-keys)]
    (sort-by :key (reduce (fn [result key]
                            (conj result {:key key :value nil}))
                          maps
                          missing))))

(ensure-mandatory-keys the-maps)
;; ({:key 1, :value nil}
;;  {:key 2, :value nil}
;;  {:key 3, :value 30}
;;  {:key 4, :value 40}
;;  {:key 5, :value nil})

- John

-- 
-- 
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your 
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Reply via email to