Clojure - finding something in a list

in.clj

 (defn in? [vs ls]
   (boolean (some (partial (set vs)) ls)))

 (in? [1 2] [3 4 2 5]) => false
 (in? [1 2] [3 1 4 2 5]) => true


(defn in? [v ls]
  (loop [[x & rs] ls]
    (if-not x
        false
        (if (= x v)
          true
          (recur [rs])))))


 (in? 3 [2 3 4]) => true
 (in? 5 [2 3 4]) => false


 (defn in? [v ls]
   (boolean (some #(= v %) ls)))
 
 (in? 3 [2 3 4]) => true
 (in? 5 [2 3 4]) => false


 (defn in? [v ls]
  (reduce (fn [_ x]
             (if (= x v)
                (reduced true)
                false)) false ls))

 (in? 3 [2 3 4]) => true
 (in? 5 [2 3 4]) => false