override def prepare()

in core/src/main/scala/com/spotify/featran/transformers/NGrams.scala [73:107]

• 33 lines of code
• 7 McCabe index (conditional complexity)

  override def prepare(a: Seq[String]): Set[String] = ngrams(a).toSet

  override def buildFeatures(
    a: Option[Seq[String]],
    c: SortedMap[String, Int],
    fb: FeatureBuilder[_]
  ): Unit =
    super.buildFeatures(a.map(ngrams), c, fb)

  private[transformers] def ngrams(a: Seq[String]): Seq[String] = {
    val max = if (high == -1) a.length else high
    val b = Seq.newBuilder[String]
    var i = low
    while (i <= max) {
      if (i == 1) {
        b ++= a
      } else if (i <= a.size) {
        val q = mutable.Queue[String]()
        var j = 0
        val it = a.iterator
        while (j < i) {
          q.enqueue(it.next())
          j += 1
        }
        b += mkNGram(q, sep)
        while (it.hasNext) {
          q.dequeue()
          q.enqueue(it.next())
          b += mkNGram(q, sep)
        }
      }
      i += 1
    }
    b.result()
  }