You are viewing a plain text version of this content. The canonical link for it is here.

Posted to user@spark.apache.org by SK <sk...@gmail.com> on 2014/11/06 19:50:04 UTC

specifying sort order for sort by value

Hi,

I am using rdd.sortBy(_._2) to get an RDD sorted by value. The default order
is ascending order. How can I get it sorted  in descending order? I could
not find an option to specify the order. 

I need to get the top K elements of the list sorted in descending order. If
there is no option to get the descending order, I would like to know if
there is a way to get the last K elements of the list sorted in ascending
order.  take(k) gets the first k elements, is there an option to get the
last K elements of an RDD ?

thanks



--
View this message in context: http://apache-spark-user-list.1001560.n3.nabble.com/specifying-sort-order-for-sort-by-value-tp18289.html
Sent from the Apache Spark User List mailing list archive at Nabble.com.

---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@spark.apache.org
For additional commands, e-mail: user-help@spark.apache.org

Re: specifying sort order for sort by value

Posted by SK <sk...@gmail.com>.

Thanks. I was looking at an older RDD documentation that did not specify the
ordering option. 



--
View this message in context: http://apache-spark-user-list.1001560.n3.nabble.com/specifying-sort-order-for-sort-by-value-tp18289p18292.html
Sent from the Apache Spark User List mailing list archive at Nabble.com.

---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@spark.apache.org
For additional commands, e-mail: user-help@spark.apache.org

Re: specifying sort order for sort by value

Posted by Akhil Das <ak...@sigmoidanalytics.com>.

Yes you can sort it in desc, you simply specify a boolean value in the
second argument to the sortBy function. Default is ascending.
So it will look like:

rdd.sortBy(_._2, false)


Read more over here
<http://spark.apache.org/docs/latest/api/scala/#org.apache.spark.rdd.RDD>

Thanks
Best Regards

On Fri, Nov 7, 2014 at 12:20 AM, SK <sk...@gmail.com> wrote:

> Hi,
>
> I am using rdd.sortBy(_._2) to get an RDD sorted by value. The default
> order
> is ascending order. How can I get it sorted  in descending order? I could
> not find an option to specify the order.
>
> I need to get the top K elements of the list sorted in descending order. If
> there is no option to get the descending order, I would like to know if
> there is a way to get the last K elements of the list sorted in ascending
> order.  take(k) gets the first k elements, is there an option to get the
> last K elements of an RDD ?
>
> thanks
>
>
>
> --
> View this message in context:
> http://apache-spark-user-list.1001560.n3.nabble.com/specifying-sort-order-for-sort-by-value-tp18289.html
> Sent from the Apache Spark User List mailing list archive at Nabble.com.
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@spark.apache.org
> For additional commands, e-mail: user-help@spark.apache.org
>
>