The difference and conversion between Seq[Int] and List[Int]

Question

When I input Seq(1,2,3) in REPL, it returns me List(1,2,3)

scala> Seq(1,2,3)
res8: Seq[Int] = List(1, 2, 3)

Th

Answer 1

Seq is a base trait (interface) for sequences and List is a concrete implementation of that interface.

Every instance of List is already a Seq so there's no need to convert anything. You can use toSeq method, but I don't see any reason to do so. To convert Seq to a List use toList method.