无法在Spark / Scala中从RDD创建Dataframe

Question

我遇到了创建Dataframe的问题，获得了重载的方法值....

    import org.apache.spark.sql.types.DataTypes._
import org.apache.spark.sql.types.{StructType, StructField, StringType, DoubleType}
import org.apache.spark.mllib.linalg.{Vector, Vectors}

val schemaString = "prediction"

val schema = StructType(schemaString.split(" ").map(fieldName ⇒ StructField(fieldName, DoubleType, true)))

val preds = predictions.select("probability").rdd.map(row => 
      (row.getAs[Vector](0).toString)).first.split(",").map(_.trim replaceAll ("[\\[\\]\"]", "")).map(_.toDouble).zipWithIndex

val sortedPreds = preds.sortBy(_._1).reverse

val doubles = sortedPreds map { case (score, toolIndex) =>  toolIndex.toDouble }

// case class myRow(i: Double, j: Double, k: Double, m: Double, z: Double)

val queryRDDRow = sc.parallelize(Seq(doubles))
val predDF = sqlContext.createDataFrame(queryRDDRow, schema)