title: Scala: sliding(N,N) vs grouped(N)
body: <p>I found myself lately using sliding(n,n) when I need to iterate collections in groups of n elements without re-processing any of them. I was wondering if it would be more correct to iterate those collections by using grouped(n). My question is if there is an special reason to use one or another for this specific case in terms of performance.</p>
  
  <pre><code>val listToGroup = List(1,2,3,4,5,6,7,8)
  listToGroup: List[Int] = List(1, 2, 3, 4, 5, 6, 7, 8)
  
  listToGroup.sliding(3,3).toList
  res0: List[List[Int]] = List(List(1, 2, 3), List(4, 5, 6), List(7, 8))
  
  listToGroup.grouped(3).toList
  res1: List[List[Int]] = List(List(1, 2, 3), List(4, 5, 6), List(7, 8))
  </code></pre>