Have you tried the following ?
Seq(1->2, 1->5, 3->6).toDS("a", "b")
then you can refer to columns by name.
FYI
On Tue, Jun 7, 2016 at 3:58 PM, Alexander Pivovarov <apivova...@gmail.com>
wrote:
> I'm trying to switch from RDD API to Dataset API
> My question is about reduceByKey method
>
> e.g. in the following example I'm trying to rewrite
>
> sc.parallelize(Seq(1->2, 1->5, 3->6)).reduceByKey(math.max).take(10)
>
> using DS API. That is what I have so far:
>
> Seq(1->2, 1->5,
> 3->6).toDS.groupBy(_._1).agg(max($"_2").as(ExpressionEncoder[Int])).take(10)
>
> Questions:
>
> 1. is it possible to avoid typing "as(ExpressionEncoder[Int])" or replace
> it with smth shorter?
>
> 2. Why I have to use String column name in max function? e.g. $"_2" or
> col("_2"). can I use _._2 instead?
>
>
> Alex
>
