实际上有元组的预定义字典顺序 https://github.com/scala/scala/blob/v2.10.0/src/library/scala/math/Ordering.scala#L358 -- 但你需要导入它 https://stackoverflow.com/questions/11102393/how-to-lexicographically-compare-scala-tuples:
import scala.math.Ordering.Implicits._
此外,您可以定义自己的顺序。
假设我想根据元组的第一个和第二个成员之间的差异来排列元组:
scala> import scala.collection.mutable.PriorityQueue
// import scala.collection.mutable.PriorityQueue
scala> def diff(t2: (Int,Int)) = math.abs(t2._1 - t2._2)
// diff: (t2: (Int, Int))Int
scala> val x = new PriorityQueue[(Int, Int)]()(Ordering.by(diff))
// x: scala.collection.mutable.PriorityQueue[(Int, Int)] = PriorityQueue()
scala> x.enqueue(1 -> 1)
scala> x.enqueue(1 -> 2)
scala> x.enqueue(1 -> 3)
scala> x.enqueue(1 -> 4)
scala> x.enqueue(1 -> 0)
scala> x
// res5: scala.collection.mutable.PriorityQueue[(Int, Int)] = PriorityQueue((1,4), (1,3), (1,2), (1,1), (1,0))