如何使用Scala聚合Spark数据帧以获得稀疏向量？

import org.apache.spark.ml.feature.VectorAssembler
import org.apache.spark.ml.linalg.Vectors

import org.apache.spark.sql.SparkSession

val spark = SparkSession.builder()
  .appName("Sparse Vector Aggregation")
  .getOrCreate()

val data = Seq(
  (1, Vectors.sparse(3, Seq((0, 1.0), (2, 2.0)))),
  (2, Vectors.sparse(3, Seq((1, 3.0), (2, 4.0)))),
  (3, Vectors.sparse(3, Seq((0, 5.0), (1, 6.0))))
)

val df = spark.createDataFrame(data).toDF("id", "features")

val assembler = new VectorAssembler()
  .setInputCols(Array("features"))
  .setOutputCol("aggregatedFeatures")

val aggregatedDf = assembler.transform(df)

aggregatedDf.show()