My alternative solutions for 4clojure #41

gistfile1.clj

(defn f [col pos]
(loop [c col cnt 1 acc []]
  (if (empty? c) 
    acc
	(recur (rest c) (inc cnt) (if (= 0 (mod cnt pos)) 
                                acc (conj acc (first c)))))))

(= (f [1 2 3 4 5 6 7 8] 3) [1 2 4 5 7 8])

(= (f [:a :b :c :d :e :f] 2) [:a :c :e])

(= (f [1 2 3 4 5 6] 4) [1 2 3 5 6])

(defn f2 [col pos]
(flatten (map #(if (= pos (count %)) 
        (drop-last %) %) 
     (partition-all pos col))))

(= (f2 [1 2 3 4 5 6 7 8] 3) [1 2 4 5 7 8])

(= (f2 [:a :b :c :d :e :f] 2) [:a :c :e])

(= (f2 [1 2 3 4 5 6] 4) [1 2 3 5 6])

Some solutions used keep-index but ones I found the most interesting used partition-all. My initial attempt used neither.