在 Traversable 对象上调用聚合函数

聚合函数对一组值执行计算并返回单一的值

package main

object Test {

  def main(args: Array[String]): Unit = {

    val t1 = Traversable(1 to 10: _*);
    println(t1);
    //List(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)


    val count = t1.count(x => x > 0); //def count(p : Function1[A, Boolean]) : Int
    println(count);
    //10

    println(
      t1.count(x => x > 5)
    ); //5


    //总和
    val sum = t1.sum; //def sum[B >: A](implicit num : scala.Numeric[B]) : B
    println(sum);
    //55


    //最大值
    val max = t1.max; //def max[B >: A](implicit cmp : Ordering[B]) : A
    println(max);
    //10


    //最小值
    val min = t1.min; //def min[B >: A](implicit cmp : Ordering[B]) : A
    println(min);
    //1
  }
}