spark--actions算子--count

import org.apache.spark.{SparkConf, SparkContext}

/**
  * Created by liupeng on 2017/6/16.
  */
object A_count {

  System.setProperty("hadoop.home.dir","F:\\hadoop-2.6.5")

  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setAppName("count_test").setMaster("local")
    val sc = new SparkContext(conf)
    //准备一下数据
    val nameList : List[Int] = List(1,2,3,4,5)
    val numbers = sc.parallelize(nameList)
    //计算数据集的数据个数，一般都是统计内部元素的个数。
    val num = numbers.count()
    println(num)
  }
}

运行结果：

5