scala - 找到 : org. apache.spark.sql.Dataset[(Double, Double)] 需要 : org. apache.spark.rdd.RDD[(Double, Double)]

Question

我收到以下错误

 found   : org.apache.spark.sql.Dataset[(Double, Double)]
 required: org.apache.spark.rdd.RDD[(Double, Double)]
    val testMetrics = new BinaryClassificationMetrics(testScoreAndLabel)

在以下代码上:

val testScoreAndLabel = testResults.
    select("Label","ModelProbability").
    map{ case Row(l:Double,p:Vector) => (p(1),l) }
val testMetrics = new BinaryClassificationMetrics(testScoreAndLabel)

从错误看来，testScoreAndLabel 的类型为sql.Dataset，但BinaryClassificationMetrics 需要一个RDD。

如何将 sql.Dataset 转换为 RDD？

Answer 1

我会做这样的事情

val testScoreAndLabel = testResults.
    select("Label","ModelProbability").
    map{ case Row(l:Double,p:Vector) => (p(1),l) }

现在转换testScoreAndLabel只需执行 testScoreAndLabel.rdd 即可实现 RDD

val testMetrics = new BinaryClassificationMetrics(testScoreAndLabel.rdd)

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