作用：返回RDD中的第一个元素
package com.atguigu
import org.apache.spark.rdd.RDD
import org.apache.spark.{SparkConf, SparkContext}
object Action {
def main(args: Array[String]): Unit = {
val conf: SparkConf = new SparkConf().setMaster("local[*]").setAppName("ADCount")
val sc = new SparkContext(conf)
val rdd: RDD[Int] = sc.makeRDD(List(1,4,3,2))
val i: Int = rdd.first()
println(i)
}
}
1
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本文标题：first()
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