After the fifth round, five more 4clojure.com solutions:

;;; Problem 50 - Split by Type (deftest test-problem-50 (let [v1 (fn [xs] (for [t (map type xs)] (filter #(= (type %) t) xs))) v2 (fn [xs] (vals (group-by type xs))) __ v2] (is (= (set (__ [1 :a 2 :b 3 :c])) #{[1 2 3] [:a :b :c]})) (is (= (set (__ [:a "foo" "bar" :b])) #{[:a :b] ["foo" "bar"]})) (is (= (set (__ [[1 2] :a [3 4] 5 6 :b])) #{[[1 2] [3 4]] [:a :b] [5 6]})))) ;;; Problem 49 - Split a sequence (deftest test-problem-49 (let [v1 (fn [n xs] [(take n xs) (drop n xs)]) __ v1] (is (= (__ 3 [1 2 3 4 5 6]) [[1 2 3] [4 5 6]])) (is (= (__ 1 [:a :b :c :d]) [[:a] [:b :c :d]])) (is (= (__ 2 [[1 2] [3 4] [5 6]]) [[[1 2] [3 4]] [[5 6]]])))) ;;; Problem 48 - Intro to some (deftest test-problem-48 (let [v1 6 __ v1] (is (= __ (some #{2 7 6} [5 6 7 8]))) (is (= __ (some #(when (even? %) %) [5 6 7 8]))))) ;;; Problem 47 - Contain Yourself (deftest test-problem-47 (let [v1 4 __ v1] (is (contains? #{4 5 6} __)) (is (contains? [1 1 1 1 1] __)) (is (contains? {4 :a 2 :b} __)) ; No longer works in CLojure 1.5+: http://clojuredocs.org/clojure_core/clojure.core/contains_q ; (is (not (contains? '(1 2 4) __))) )) ;;; Problem 46 - Flipping out (deftest test-problem-46 (let [v1 (fn [f] #(f %2 %)) __ v1] (is (= 3 ((__ nth) 2 [1 2 3 4 5]))) (is (= true ((__ >) 7 8))) (is (= 4 ((__ quot) 2 8))) (is (= [1 2 3] ((__ take) [1 2 3 4 5] 3))))) (run-tests)