回复：Re: Re: how to select first 50 value of each group after group by?

：罗辉 <luohui20...@sina.com>, user <user@spark.apache.org> 主题：Re: Re: how to select first 50 value of each group after group by? 日期：2016年07月07日 20点38分 Hi, I can try to guess what is wrong, but I might be incorrect. You should be careful with window frames (you define them via the

Re: Re: how to select first 50 value of each group after group by?

PI I want , because there > are some values have same pv are ranked as same values. And first 50 rows > of each frame is what I'm expecting. the attached file shows what I got by > using rank. > Thank you anyway, I learnt what rank could provide from your advice. > >

Re: Re: how to select first 50 value of each group after group by?

vide from your advice. > > ---- > > ThanksBest regards! > San.Luo > > - 原始邮件 - > 发件人：Anton Okolnychyi <anton.okolnyc...@gmail.com> > 收件人：user <user@spark.apache.org> > 抄送人：luohui20...@sina.com > 主题：Re: how to select firs

回复：Re: how to select first 50 value of each group after group by?

advice. ThanksBest regards! San.Luo - 原始邮件 - 发件人：Anton Okolnychyi <anton.okolnyc...@gmail.com> 收件人：user <user@spark.apache.org> 抄送人：luohui20...@sina.com 主题：Re: how to select first 50 value of each group after group by? 日期：2016年07月06日 23

Re: how to select first 50 value of each group after group by?

The following resources should be useful: https://databricks.com/blog/2015/07/15/introducing-window-functions-in-spark-sql.html https://jaceklaskowski.gitbooks.io/mastering-apache-spark/content/spark-sql-windows.html The last link should have the exact solution 2016-07-06 16:55 GMT+02:00 Tal

Re: how to select first 50 value of each group after group by?

You can use rank window function to rank each row in the group, and then filter the rowz with rank < 50 On Wed, Jul 6, 2016, 14:07 wrote: > hi there > I have a DF with 3 columns: id , pv, location.(the rows are already > grouped by location and sort by pv in des) I wanna

how to select first 50 value of each group after group by?

hi thereI have a DF with 3 columns: id , pv, location.(the rows are already grouped by location and sort by pv in des) I wanna get the first 50 id values grouped by location. I checked the API of dataframe,groupeddata,pairRDD, and found no match. is there a way to do this naturally?