The NearestNeighbor#classify() method.

nearest_neighbor_v4.scala

class NearestNeighbor( library: List[Instance]) {
	def classify( query: Instance): Instance = {
		val distanceMeasurements = library.map( example => (query.distanceTo( example), example))
		val sortedDistanceMeasurements = distanceMeasurements.sortWith(( e1, e2) => ( e1._1 - e2._1) < 0)
		val nearestExample = sortedDistanceMeasurements.head._2
		query.assignClassLabel( nearestExample.classLabel)
	}
}