Scala type mismatch how to convert Iterable[Double] to Double

Question

I am trying to modify this example as follows:

@BigQueryType.fromQuery("SELECT weight_pounds FROM [bigquery-public-data:samples.natality]")
  class Row

@BigQueryType.toTable
  case class Result(weight_pounds: Double)

sc.typedBigQuery[Row]()
      .map(r => r.weight_pounds.getOrElse(0.0)) // return 0 if weight_pounds is None
      .top(100)
      .map(x => Result(x))
      // Convert elements from Result to TableRow and save output to BigQuery.
      .saveAsTypedBigQueryTable(
        Table.Spec(args("output")),
        writeDisposition = WRITE_TRUNCATE,
        createDisposition = CREATE_IF_NEEDED
      )

Above gives me following error:

[error] /Users/me/scio/scio-examples/src/main/scala/com/spotify/scio/examples/foo.scala:66:24: type mismatch;
[error]  found   : Iterable[Double]
[error]  required: Double
[error]       .map(x => Result(x))
[error]                        ^

How can I fix this?

Answer 1

诀窍是在top(100)之后添加一个flatMap(x => x) )