Common Seq operations

// scala code
object Test {
  // Seq operations
  val xs = List(1, 2, 3, 4, 5)
  xs.isDefinedAt(2)
  xs(2)
  xs.lengthCompare(xs.size) // same length, returns 0
  xs.lengthCompare(xs.size + 1) // less than. returns -1
  xs.lengthCompare(xs.size - 1) // less than. returns 1
  xs.indexOf(5) // 4
  val ys = List(1, 2, 2, 3, 4)
  ys.indexOf(2) // 1
  ys.lastIndexOf(2) // 2
  ys.indexOfSlice(List(2, 2)) // 1
  val zs = List(1, 2, 2, 3, 2, 2, 4)
  zs.lastIndexOfSlice(List(2, 2)) // 4
  xs.indexWhere(_ == 2)
  val xs1 = List(1, 2, 2, 3, 2, 2, 2, 2)
  xs1.segmentLength(_ == 2, 1)
  xs1.prefixLength(_ > 1)
  xs.padTo(10, 11)

  val xs2 = List(1, 1, 1, 1, 1, 1, 1)
  val xs3 = List(2, 2, 2)
  xs2.patch(1, xs3, 4) // drop the last 4 elems of xs2, starting from index 1, patch with xs3
  xs.updated(1, 11)
  // xs(1) = 11 // same as the above line, only for mutable collections
  xs.reverse.sorted
  xs.sortWith((x, y) => x < y)
  xs.sortWith((x, y) => x > y)
  xs.sortBy(_ % 3) // transform elems with modulo 3 and then sort
  xs.reverseMap(_ + 1)
  xs.startsWith(List(1, 2))
  xs.endsWith(List(4, 5))
  xs.contains(5)
  xs.containsSlice(List(1, 2))
  (xs.corresponds(xs.map(_ + 1)))((x, y) => y - x == 1) // test whether each pair (x_i, y_i) satisfies a predicate
  xs.intersect(xs.tail).sameElements(xs.tail)
  xs.diff(xs.tail).sameElements(List(xs.head))
  (List(xs.head) union xs.tail) == xs
  List(1, 1, 2).distinct == List(1, 2)
}