值查找不是org.apache.spark.rdd.RDD的成员

Question

This is my whole sample code:

package trouble.something

import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.rdd.RDD

object Stack {
  val conf = new SparkConf().setMaster("local[*]").setAppName("app")
  val sc = new SparkContext(conf)

  def ExFunc[Int](looku: RDD[(Int, Long)]) {
    val ke = 3
    looku.lookup(ke);
  }

  def main(args: Array[String]){
    val pi: RDD[(Int, Long)] = sc.parallelize(Seq((1, 9L), (2, 11L)))
    pi.lookup(3)

    val res = ExFunc[Int](pi)
  }
}

When I execute the following line, it executes correctly without any errors and produces output

pi.lookup(3)

But, when I pass pi to a function, and use lookup as below, then i get an error

val res = ExFunc[Int](pi)

Passing pi to below function

def ExFunc[Int](looku: RDD[(Int, Long)]) {
  val ke = 3
  looku.lookup(ke);
}

Then I get this error message:

Error:(27, 11) value lookup is not a member of org.apache.spark.rdd.RDD[(Int, Long)]
    looku.lookup(ke);

Can anybody help me correcting this error

Answer 1

The function shouldn't be generic. Just remove type parameter

def ExFunc(looku: RDD[(Int, Long)]) {
  val ke = 3
  looku.lookup(ke);
}

To create generic function provide ClassTag , for example

import scala.reflect.ClassTag

def ExFunc[T : ClassTag](looku: RDD[(T, Long)], ke: T) {
  looku.lookup(ke);
}