Scala filter tuples (x, y) == (y, x)

Question

I have a list of tuples, for example:

  (0,2)
  (0,5)
  (2,0)
  (2,5)
  (3,4)
  (4,3)
  (5,0)
  (5,2)

There are some tuples where (x, y)

Answer 1

How about first sorting the tuple pairs internally. I believe this technique would pass through your list just twice since distinct is advertised as O(n) complexity:

val ts = List((0,2),(0,5),(2,0),(2,5),(3,4),(4,3),(5,0),(5,2))

ts.map{ case (x,y) if x < y => (y,x) case (x,y) => (x,y) }.distinct