Question

I was wondering what’s an easy way to sort a List[(String, String)] by the first string in the tuple alphabetically while removing all duplicates for the second string in the tuple.

Thanks for the suggestions!

Answer 1

We could run a performance test?

val items = List("a" -> 0, "b" -> 1, "c" -> 0, "d" -> 0, "e" -> 1)
items.groupBy(_._2).toList
     .sortBy(_._2.head._1)(new Ordering[String]() { 
         override def compare(x: String, y: String) = { -x.compareTo(y) } 
     })
     .map(e => (e._2.head._1 -> e._1))

Result:

List((b,1), (a,0))