Partition a collection into “k” close-to-equal pieces (Scala, but language agnostic)

Question

Defined before this block of code:

• dataset can be a Vector or List
• numberOfSlices is an Int

Answer 1

If the behavior of xs.grouped(xs.size / n) doesn't work for you, it's pretty easy to define exactly what you want. The quotient is the size of the smaller pieces, and the remainder is the number of the bigger pieces:

def cut[A](xs: Seq[A], n: Int) = {
  val (quot, rem) = (xs.size / n, xs.size % n)
  val (smaller, bigger) = xs.splitAt(xs.size - rem * (quot + 1))
  smaller.grouped(quot) ++ bigger.grouped(quot + 1)
}