H2O 隐式转换引发编译错误

Question

下面的代码在分配 H2OFrame 时抛出错误，很可能是隐式转换有问题。错误是：

类型不匹配；发现：org.apache.spark.h2o.RDD[Int]（扩展 to) org.apache.spark.rdd.RDD[Int] 需要： org.apache.spark.h2o.H2OFrame（扩展为）water.fvec.H2OFrame

和代码：

import org.apache.spark.h2o._

import org.apache.spark._
import org.apache.spark.SparkContext._

object App1 extends App{

         val conf = new SparkConf()
         conf.setAppName("Test")
         conf.setMaster("local[1]")
         conf.set("spark.executor.memory","1g");

         val sc = new SparkContext(conf)

         val rawData = sc.textFile("c:\\spark\\data.csv")        
         val data = rawData.map(line => line.split(',').map(_.toDouble))    
         val response: RDD[Int] = data.map(row => row(0).toInt)

         val h2oResponse: H2OFrame = response   // <-- this line throws the error
         sc.stop

}

Answer 1

你所缺少的只是 h2oContext 的隐含

import h2oContext.implicits._
val h2oResponse: H2OFrame = response.toDF()