df.groupBy($"col1").agg(count($"col1").as("c")).show
On Thu, May 21, 2015 at 3:09 AM, SLiZn Liu <sliznmail...@gmail.com> wrote:
> Hi Spark Users Group,
>
> I’m doing groupby operations on my DataFrame *df* as following, to get
> count for each value of col1:
>
> > df.groupBy("col1").agg("col1" -> "count").show // I don't know if I should
> > write like this.
> col1 COUNT(col1#347)
> aaa 2
> bbb 4
> ccc 4
> ...
> and more...
>
> As I ‘d like to sort by the resulting count, with .sort("COUNT(col1#347)"),
> but the column name of the count result obviously cannot be retrieved in
> advance. Intuitively one might consider acquire column name by column index
> in a fashion of R’s DataFrame, except Spark doesn’t support. I have Googled
> *spark
> agg alias* and so forth, and checked DataFrame.as in Spark API, neither
> helped on this. Am I the only one who had ever got stuck on this issue or
> anything I have missed?
>
> REGARDS,
> Todd Leo
>
>
