scala - Remove unique items from sequence -


this question has answer here:

i find lot how remove duplicates, elegant way remove unique items first , remaining duplicates.

e.g. sequence (1, 2, 5, 2, 3, 4, 4, 0, 2) should converted (2, 4).

i can think of using for-loop add count each distinct item, imagine scala has more elegant way achieve this.

also keep in mind i => i can replaced identity , map(_._1) keys, this:

seq(1, 2, 5, 2, 3, 4, 4, 0, 2).groupby(identity).filter(_._2.size > 1).keys.toseq

this countbykey method, such 1 can found in spark's api, useful.


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