title: Split a vector into vector of vectors in clojure instead of vector of lists
body: <p>The clojure documentation of <a href="http://clojuredocs.org/clojure_core/clojure.core/split-at" rel="nofollow noreferrer">split-at</a> states that it takes a collection of elements  and returns a <a href="http://clojure.org/data_structures#vectors" rel="nofollow noreferrer">vector</a> of two <a href="http://clojure.org/data_structures#Lists" rel="nofollow noreferrer">lists</a>, each containing elements greater or smaller than a given index:</p>
  <pre><code>(split-at 2 [1 2 3 4 5])
  [(1 2) (3 4 5)]
  </code></pre>
  <p>What I want is this:</p>
  <pre><code>(split-at' 2 [1 2 3 4 5])
  [[1 2] [3 4 5]]
  </code></pre>
  <p>This is a collection cut into two collections that keep the order of the elements (like vectors), preferably without performance penalties.</p>
  <p>What is the usual way to do this and are there any performance optimized ways to do it?</p>