Returns true if coll implements count in constant time
user=> (counted? [:a :b :c]) true user=> (counted? '(:a :b :c)) true user=> (counted? {:a 1 :b 2 :c 3}) true user=> (counted? #{:a :b :c}) true user=> (counted? "asdf") false user=> (counted? (into-array Integer/TYPE [1 2 3])) false
;; Lazy sequences are not counted? (counted? (map inc (range 5))) ;;=> false
If coll is counted? returns its count, else will count at most the first n elements of coll using ...
counted?
