小编use*_*424的帖子

在 SPARK 2.0 中使用 SCALA 将 pre-LDA 转换转换为数据帧时遇到编译错误。抛出错误的具体代码如下：

val documents = PreLDAmodel.transform(mp_listing_lda_df)
  .select("docId","features")
  .rdd
  .map{ case Row(row_num: Long, features: MLVector) => (row_num, features) }
  .toDF()

完整的编译错误是：

Error:(132, 8) value toDF is not a member of org.apache.spark.rdd.RDD[(Long, org.apache.spark.ml.linalg.Vector)]
possible cause: maybe a semicolon is missing before `value toDF'?
      .toDF()

这是完整的代码：

import java.io.FileInputStream
import java.sql.{DriverManager, ResultSet}
import java.util.Properties

import org.apache.spark.SparkConf
import org.apache.spark.ml.Pipeline
import org.apache.spark.ml.clustering.LDA
import org.apache.spark.ml.feature.{CountVectorizer, CountVectorizerModel, RegexTokenizer, StopWordsRemover}
import org.apache.spark.ml.linalg.{Vector => MLVector}
import org.apache.spark.mllib.clustering.{LDA => oldLDA}
import org.apache.spark.rdd.JdbcRDD
import org.apache.spark.sql.types.{StringType, StructField, …