I have a dataframe like this

df.show(5) kv |list1 |list2 |p [k1,v2|[1,2,5,9 |[5,1,7,9,6,3,1,4,9] |0.5 [k1,v3|[1,2,5,8,9|[5,1,7,9,6,3,1,4,15] |0.9 [k2,v2|[77,2,5,9]|[0,1,8,9,7,3,1,4,100]|0.01 [k5,v5|[1,0,5,9 |[5,1,7,9,6,3,1,4,3] |0.3 [k9,v2|[1,2,5,9 |[5,1,7,9,6,3,1,4,200]|2.5 df.count() 5200158 

I want to get the row that have maximum p, this below works for me but I don't know if there is another cleaner way

val f = df.select(max(struct( col("pp") +: df.columns.collect { case x if x != "p" => col(x) }: _* ))).first() 

2 Answers

Just order by and then take:

import org.apache.spark.sql.functions.desc df.orderBy(desc("pp")).take(1) 

or

df.orderBy(desc("pp")).limit(1).first 

You can also use Window-Functions, this is especially useful if the logic of selecting the row gets more complex (other than global min/max) :

import org.apache.spark.sql.expressions.Window df .withColumn("max_p",max($"p").over(Window.partitionBy())) .where($"p" === $"max_p") .drop($"max_p") .first() 

Your Answer

Sign up or log in

Sign up using Google Sign up using Facebook Sign up using Email and Password

Post as a guest

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy