Say, I have a sequence of strings as an input and I want to get a new immutable Seq which consists of elements of the input and an item "c". Here are two methods that I've discovered to be working:

  1. assert(Seq("a", "b", "c") == Seq("a", "b") ++ Seq("c")) - the problem with this one is that it seems that instantiating a temporary sequence (Seq("c")) just for the sake of the operation is rendundant and will result in overhead
  2. assert(Seq("a", "b", "c") == List("a", "b") ::: "c" :: Nil) - this one restricts the type of input collection to be a List, so Seq("a", "b") ::: "c" :: Nil won't work. Also it seems that instantiating a Nil may aswell result in overhead

My questions are:

  1. Is there any other way of performing this operation?
  2. Which one is better?
  3. Isn't Seq("a", "b") ::: Nil not being allowed a flaw of Scala's developers?
list scala seq
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