Hey Spark users, I'm trying to group by a dataframe, by appending occurrences into a list instead of count.
Let's say we have a dataframe as shown below: | category | id | | -------- |:--:| | A | 1 | | A | 2 | | B | 3 | | B | 4 | | C | 5 | ideally, after some magic group by (reverse explode?): | category | id_list | | -------- | -------- | | A | 1,2 | | B | 3,4 | | C | 5 | any tricks to achieve that? Scala Spark API is preferred. =D BR, Todd Leo
